Forgive me, I'm sure this has been asked and answered in this forum, but I have no idea how to search within just this forum. Searches seem to be only across every forum and yield thousands of results. We have less than a quarter of our recipient mailboxes on O365 so far, and this hasn't come up until now. I assumed it would be straightforward, but it doesn't appear so. I have a user who has a primary SMTP that differs from her display name (it matches her AD account). It was set up that way before her mailbox was migrated to O365. She has requested that her primary SMTP address be changed to match her display name. Her AD account is MJones. Instead of Display Name: Mary Smith; SMTP: MJones@mycorp.com; smtp: email@example.com she now wants Display Name: Mary Smith; SMTP: MSmith@mycorp.com; smtp: firstname.lastname@example.org She also currently has smtp: email@example.com and smtp:firstname.lastname@example.org In the Office 365 Admin Center, I have the check box available for setting a secondary email address as primary, but since this is a hybrid environment, I know I have to make such settings on prem and let them replicate. When I look at the O365 mailbox object in the on prem EAC, I do not see any way of setting any of the addresses as primary. How do I properly make this change? Am I overlooking something in on-prem EAC, do I use Set-RemoteMailbox, or do I edit AD? The other question I have is regarding the tenant SMTP addresses. Do I need to create additional secondary tenant SMTP addresses (mycorptenant.mail.onmicrosoft.com and mycorptenant.onmicrosoft.com in my example) to match the new primary SMTP address? Looking ahead, what is the proper way to change someone's name when for example a woman gets married (or divorced)? Thank you very much for your help with this.