If you try contacting OR support, expect them to propose ending the tenancy, refunding the deposit and creating a new tenancy with a new deposit.
If that happens and you still want OR to change LL name on the deposit account, @Tim43 may be able to tell you whom to contact in OR to get it sorted
(See their reply to him Change of Landlord when tenants are stil in property - #52 by Tim43 )
Good Luck