How to plan an Office 365 migration without disrupting business operations

Start by listing mailboxes, aliases, shared addresses, and the applications that send email. Agree on what must move and who will validate each account. Prepare the destination accounts and explain the rollout to users. Confirm DNS ownership, backup requirements, and the cutover window before changing mail routing. After the move, check incoming and outgoing messages, calendars, mobile access, and application mail delivery. Keep a clear issue list and a named support contact for follow-up.