Domain migration with UPN suffix the same as target domain name

Hello,

We are currently thinking of migrating domain (internal.local), this domain has UPN suffix (external.local). UPN suffix is necessary for Office 365.

We would like to migrate to new domain (external.local), which is the same as UPN suffix used.

Is it possible? What is the best way to do this?

Thanks in advance,

Pēteris