AI Voice Agents for Trial-to-Paid Conversion Calls: A Sales Call

AI voice agents for trial-to-paid conversion calls phone trial users who showed intent, ask what they wanted to get done, answer from your product docs, then book sales or have your billing system send the upgrade link. Because the call sells, it generally needs prior express written consent, captured on the trial form before any call.

Key Takeaways

• A trial-to-paid call sells, so it generally needs prior express written consent.
• Call on a trial event from your product, not on every signup.
• The agent quotes only prices your system returns and never takes card details.

This post is part of our guide to AI voice agents for SaaS and subscription businesses. The guide's section "Getting customers in: trial and onboarding calls" puts it plainly: "The trial-to-paid call is a sales call." Here is that call in full, run in Dograh, an open-source, self-hostable voice agent platform.

Why a trial-to-paid call counts as a sales call

A trial-to-paid call exists to turn a free user into a paying one, and the rules treat that as selling. The FCC's rule at 47 CFR 64.1200 defines telemarketing as "the initiation of a telephone call or message for the purpose of encouraging the purchase or rental of, or investment in, property, goods, or services, which is transmitted to any person." A call that asks a trial user to buy a plan fits that wording.

The same rule bars "any telephone call that includes or introduces an advertisement or constitutes telemarketing, using an automatic telephone dialing system or an artificial or prerecorded voice" to mobile numbers, "other than a call made with the prior express written consent of the called party". In its February 2024 declaratory ruling, the Federal Communications Commission (FCC) confirmed that this "artificial or prerecorded voice" rule covers AI-generated voices.

A plain trial-expiry reminder is different. If it only says when the trial ends and how to keep access, with no offer, it is generally a service call that needs prior express consent. Add an upgrade offer or a discount and it generally becomes telemarketing again.

The consent box on the trial signup form

Written consent has a defined shape. Paragraph (f)(9) of the rule describes "an agreement, in writing, bearing the signature of the person called that clearly authorizes the seller to deliver or cause to be delivered to the person called advertisements or telemarketing messages using an automatic telephone dialing system or an artificial or prerecorded voice, and the telephone number to which the signatory authorizes such advertisements or telemarketing messages to be delivered."

It must also tell the person they are "not required to sign the agreement (directly or indirectly), or agree to enter into such an agreement as a condition of purchasing any property, goods, or services." An electronic signature counts where federal or state law recognises it, which generally covers a web form checkbox.

On a trial form, that generally means its own unticked box, apart from the terms of service. The line names your company, says you may call about plans using AI or prerecorded voices, shows the number it covers, and says agreeing is not a condition of buying. Store the box's state, the exact wording shown and the time with the account. No box, no AI call: those users get email or a person instead. Our post on abandoned-cart recovery applies the same rule at checkout.

B2B trials are no way around this. The rule's residential clause covers "any residential line", so a trial user's work landline generally falls outside it. The mobile clause covers "any telephone number assigned to a ... cellular telephone service" whoever pays the bill, and most trial signups give a mobile. So treat every trial call as needing written consent. State laws can add their own rules. This is general information, not legal advice; confirm your position with counsel.

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Which trial users to call, and when

Call on intent. A user who connected data, invited a colleague or hit a plan limit, with a few days left in the trial, is the call worth making.

Your product or billing system decides who qualifies. When the event fires and the consent flag is set, it starts the call through the API Trigger, with the facts the agent needs in initial_context: first name, plan, trial end date and what the user actually did. Because your system decides, a user who upgraded an hour ago, or said "stop" yesterday, never gets the call. Our post on API triggers shows the request.

Campaigns can also dial a daily list you upload. To stop calling someone mid-campaign, pause the campaign and start a new one from a corrected list.

How the call runs, from greeting to next step

The call opens with Greeting Text, the fixed line Dograh plays word for word as the call connects. It names your company exactly. Recording starts as the call connects, so any recording notice goes first. If you want to tell callers they're speaking with an automated assistant, or your location requires it by law, write that in the Greeting Text too. Give each per-call variable a fallback, such as {{first_name | there}}, so a missing value still reads naturally.

A phone number or a name only finds the account, but it does not prove who is speaking. So before the agent mentions anything the user did in the product, tell it in the prompt to ask for an approved check, such as the email the trial was opened with, checked against your system.

Then it asks what the user was trying to get done. Questions about features get answers from your own docs, uploaded to the Knowledge Base as PDF, DOCX, DOC, TXT, JSON or MD files of up to 5 MB each.

Price questions go to your pricing system through an HTTP API tool, and the agent quotes only what comes back. Tell it in the prompt never to offer a discount the system did not return.

The call ends with one next step. An HTTP API tool books a call with your sales team in your calendar or CRM, or another HTTP API tool asks your billing system to send its upgrade link by email or text, and the user upgrades there. Dograh has no payment feature and no keypad tool. Recordings and transcripts keep whatever is said, so the call never asks for a full account, card or Social Security number; use a short check such as the last four digits, and send payment links by text or email from your own system.

The agent records the user's goal and any objection as they stated them, and a Webhook node sends them to your CRM after the call. A user who is stuck on setup needs help first, and that is a different call with a lighter consent rule: AI voice agents for customer onboarding calls in SaaS.

Stop requests, opt-outs and handing over

A user who says "stop calling me" has opted out. Dograh keeps no do-not-call list. When a caller opts out, an HTTP API tool writes it to your own list, and you remove those numbers before the next campaign upload. The do_not_call call tag records the request but never blocks a later call.

The FCC has also adopted a rule on opt-outs from sales calls, which is not yet in effect. In its new order, it says "Revocation requests made in response to robocalls that contain an advertisement or constitute telemarketing revoke consent to all future robocalls containing an advertisement or that constitute telemarketing from that caller." So, once the rule takes effect, one "stop" on a trial call generally ends every AI sales call from you to that number. Confirm your position with counsel.

A user ready to talk contracts or volume goes to a person. Transfer Call works on Twilio, Telnyx and Asterisk ARI. It passes no summary by default; on Twilio it can play a short spoken introduction to both people. Write the details to your system with an HTTP API tool before the transfer. Web calls cannot transfer, so test this on a real phone line. If nobody answers, the caller stays with the agent; tell it in the prompt to offer a callback.

The same consent logic covers offers to customers who already pay, in AI voice agents for upsell and cross-sell. Self-hosted Dograh has no per-minute platform fee (servers, model keys and phone minutes still cost); Dograh Cloud has a 1¢-a-minute platform fee.