A custom domain for sending your notices of meeting
Register your firm's domain and send notices of meeting from your own addresses instead of Alex's.
Send your emails from your own domain. In organisation settings, the Emails tab registers your sending domain. Alex shows the DNS records to publish, with a status for each, then verifies the domain. Availability depends on your plan.

Notices of meeting sent in your name
Your notices of meeting now go out from your address. Once the domain is verified, admins declare senders: a name and an address on that domain. When you send a notice of meeting, pick one of them, and the email goes out from your address instead of Alex's. The preview and the send window show the chosen sender.
