Storage Migration Service - Update credentials without discarding data from later phases?

Using SMS, I successfully transferred data from an old file server to a new VM.  However, I had to delay finishing the migration for a few weeks.  In that time, I changed my password.  Now when I try to Transfer Differences for the SMS job, I get an Access Denied error.  When I try to change the stored credentials for the SMS job, it warns me that it will discard data from later phases of the process.  Does that mean I will have to wipe the new server and re-do the data transfer from scratch?  I'd prefer not to have to do that again if I can avoid it.

Is there a way I can change the stored credentials for the SMS job without discarding the data transfer info?  Thank you for any help you can provide.