You can learn from this article how to remove a GoToAssist user from the classic GoTo Admin Center.

1. Sign in to the classic GoTo Admin Center at https://admin.logmeininc.com.
2. From Manage Users, click on the user you want to remove the GoToAssist license from.
3. Under Products, select Edit and then clear the checkbox next to Agent for GoToAssist Remote Support (mobile will also be cleared automatically).
4. Click Save.