Deleting a System From a Local Repository 
Use
You may delete all the metadata that belongs to one R/3 system from a local repository file.
If you wish to delete all the data in a local repository file, you can delete the SDB file itself.
Prerequisites
You must be logged off from any live R/3 connection or from any other local repository you are working with. To disconnect from the other system or local repository choose the Logoff button or choose FileàLogoff.
Procedure