1. In Accounts Payable or Payroll, select Banks.
  2. Select the appropriate Bank at the top.
  3. Click Edit Account Details. 
  4. Select the Payments tab, select AP Electronic Funds Transfer or PY Electronic Funds Transfer. 
  5. At the bottom of the tab, select "Edit Payment Options". 
  6. Select EFT General. 
  7. Edit the Company ID prefix.