How to change priority of newly created Bank Account of any Supplier to 1

Hello ,

I have a supplier XYZ. There are three bank accounts A1, A2, A3 is attached with it's single site with priority 1,10 and 11 respectively.

Now a new bank account A4 has been created and assigned to the same supplier site. It's priority is coming as 12 by default.

Business wants to change the priority of A4 to 1 and decrease the priority of A1,A2, A3 to 10,11 & 12 respectively. But some how, only decreasing the priority of A1 to 10 and subsequently priority of A2 to 1 is working .

Please let me know, hoe to achieve that.

Regards,

Bhaskar