Office 365 Migration

We recently migrated to Office 365 and have been operational for a month.  We discovered that one of the user mailboxes did not migrate correctly.   Exchange services have been shut off on the on-premise server since migration.  Can I safely restart Exchange services on the on-premise server and reconnect to the problematic mailbox without disrupting Office 365 operations?  I would like to verify what the mailbox looked like just prior to migration.