We are in hybrid model.let me explain my scenario below.
Forest A Forest B
Exchange 2016 Exchange online
All exchange mailboxes migrated to office 365 and keeping exchange server in forest A for hybrid. now customer wants to change primary smtp address for all mailboxes. example from contoso.com to fabrikam.com.then decommision the hybrid server in forest A and install hybrid in forest B. is it possible to migrate hybrid same version from one forest to another forest and also they will change the namespaces as per their standard.