Recreate default System Logon Account in BE 2012 in CASO

Do anyone know how to recreate default System Logon Account in BE 2012 in Central Administration Server.

I follow the following procedure to do but it failed to do.

Before deleting the existing SLA, I create a new temporary account. Also, change the Service credentials to this new temporary account and make it as Default account.

Then choose temporary account and edit "Replace" button in managed logon account dialog box to replace all the jobs and backup selections.Then choose "System  Logon Account (SLA) and click "Delete".

The dialog box show "the account System Logon Acccount cannot be deleted because the following users have selected it as their default logon account  and one or more of them are currently logged on the media server.