I know I have changed a companion pass flight in the past online with limited trouble. Currently I have one booked that I need to change, but I get this message at the top every time I try to do it online "Oh no! We're sorry, but there was a problem processing your request. Please go back and try again. #ROF5510". I think the issue is both legs of the flight I have booked had a schedule change, so they automatically re-booked us for the new flights. That plus the companion ticket seem to cause Delta's system to get confused. The schedule change isn't big enough to get a free change with no airfare difference. I'm actually looking to change destinations and the paid ticket would be cheaper anyways. I know there needs to be inventory available in the correct fare class, and it looks like there is.

So from a practical standpoint in this situation, would it be easier to call Delta and get an agent to make these changes? Or just cancel the flight.. get the ecredit for the paid portion and rebook on my own using the reissued companion pass?
The terms state that if I cancel I will get the Companion Pass re-issued (it expires 3/31). I would plan to book a new flight that completes before then, so no issues there.