Hi! You would post the primary payment, transfer the full balance remaining for the code to the secondary, then do the final write off after secondary insurance processes the payment... example: D0120 is $100. Delta pays their contracted fee of $40, you post the Delta payment, transfer the $60 remaining balance to Health Partners, send the claim to Health Partners with all of the primary info and payments entered (this varies per software- most important thing is that Health Partners receives the info that pt has primary ins and the Primary EOB so that they don't over pay) then once Health Partners processes and pays, you write off the remaining amount (ex: Health Partners contracted rate is $45- Delta paid $40, Health Partners pays $5, you write off remaining $55). Hope this helps!