Visionary User to Proton Workspace

Hello,

I have a Visionary plan with multi-user support enabled. One of the members of my organization has their own Proton account (it was set up as a private user and is not administratively managed by me), and I assigned them an address on a custom domain connected to my organization.

I would like to separate this member from my organization so they can subscribe to Proton Workspace independently. Ideally, the custom domain associated with their address would move with them, as it's used only for their address.

Could you please advise:

1. Whether their account and mailbox data can be migrated out of my organization into a standalone subscription?
2. What the process is for detaching the custom domain from my organization and re-verifying it under their new account?
3. Anything I should do on my end (order of operations, DNS/MX considerations) to avoid mail loss during the transition?

Thank you.