can I update customer's account_number ?

I imported customer data from one instance to the other in custom tables . they refer to account_number created in hz_cust_accounts_all  and the customer number in dev instance are not the same and there is no plan of refresh in near future.

Data in custom table is stored in XMLDatatype and it will be very tedious to find the field and replace the customer number to match it with the dev system.

Can I update customer's account_number ? If yes then how ?

thanks