Cloud domain migration

[Ugnius Aušra]

Hello Atlassian community!

I'm asking for advice on how to prepare for migration and which option to choose.

I can explain our need:

In our jira organization there's 50 users working.

40 users are from our company, 10 from client.

We want to disassociate, because even domain name is not correct for our company.

We want to do migration to a new domain.

Questions is:

Can i migrate from existing organization leaving only one project left?

How about customer portals? Our client has one customer portal, and we also on different projects.