A. In the Exchange Management Console, under the Recipients navigation node, select Mailbox. All known recipients are displayed. If you right-click a user and select Move Mailbox, you can select the new server, storage group (SG) and database, action to take with any corrupted mailbox items, and the time at which to move it.
Before a move is attempted, the move-mailbox procedure performs the following checks (use -ValidateOnly in PowerShell to just perform the checks): verify that the user exists, check source and target credentials (performed by connecting to the server), check mailbox size limit against the target database, block system mailbox moves, fail if source user doesn't have a mailbox, and test whether the target database is mounted.