If the sim is registered under the same name as the bank acct owner u don't have to do anything....if the sim have a different name just go to the telco u are using and updated to your name if under your girlfriends name bring her along after the verification at the relco proceed to the bank and get updated.....if you can't do it time most probably your mobile banking get suspended but u still can use your card or walkin to the bank with bank book to do transaction.....and u can reuse the mobile app once everything have been updated at the bank