> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vapify.agency/llms.txt
> Use this file to discover all available pages before exploring further.

# Migrate Existing Clients

> Bring clients you already serve elsewhere onto Vapify, one sub account at a time.

## Overview

If you're already running voice AI for clients directly through Vapi or Retell, this guide covers moving them onto Vapify without disrupting service.

## The path

1. Create a sub account for each existing client using [Create Your First Client](/getting-started/create-your-first-client) as the template. One client, one sub account, always.
2. Assign each client's existing provider assistant (already built in Vapi/Retell) using [Assign an AI Assistant](/getting-started/assign-an-ai-assistant). You don't need to rebuild the assistant. Vapify only assigns and prices existing assistants.
3. Match your current pricing in [Configure Pricing](/getting-started/configure-pricing) so the client's bill doesn't change unexpectedly at cutover.
4. Invite each client using [Invite Your Client](/getting-started/invite-your-client), timed so their new login is ready before you retire their old access.
5. Set each sub account's Billing Start Date to the actual cutover date. It can be backdated, but only set once.

<Warning>
  The Billing Start Date is permanent once set. If you're migrating several clients at once, verify pricing and assistant assignment for each one before setting it.
</Warning>

## Related Articles

* [Manage Multiple Clients](/guides/manage-multiple-clients): operating many sub accounts at once
* [Understanding Sub Accounts](/running-your-agency/understanding-sub-accounts): the isolation model each migrated client gets