Transfer ownership from Employee to intenal party

In our initial test environment, we created an item instance, and at the time, we were not able to get it to assign to the Internal Party for ownership, but we were able to give it to an employee for ownership. We now want to update the ownership to the Internal Party. I have tried to do this by using the Item Instance update form in the Agent User responsibility, but the form as asking for an account number, even though we have set this party up as the Internal Party and assigned it as such in the IB Parameters