Hi Avril best thing if you want the account to continue is contact the bank and have your name removed from the account before you petition for your bankruptcy.
If the account is already frozen after your having already been declared bankrupt then you need to contact the OR if you can prove that the funds within the account were in part or in whole belonging to the other account holder.
EG if there were £1000 in the account and the statements show the joint holder had just been paid £1000 in salary, the money could be released to them.