I have a domain where the email addresses are different to the UPN's. So in AD, I have a UPN of john.surname@domain.com and in Office 365, I have a UPN/email address of john@domain.com. I would like to sync these and am wondering what the best way to go about it is.
The AD UPN should remain and the email address in O365 should also remain. Could I just add a proxy address of john.surname@domain.com (current O365 email) along with the onmicrosoft one to AD and this would suffice?
Thanks for any help.