Dear,
"You want blank Field but Required Field "
One query from my side as below ,
How system will be leave the Blank as a " Required Field "in Customer Master ? If you not maintain ,How system will be saved Completely with out any Error ?
Note : Already my dear Jelena Perfiljeva has explained clearly . You have to explain the User as convenience to another way and also explain ,how SAP treats the Fields in Master Data Level when we maintain Required /Optional/Suppress .
If you have any doubts please let me know.