I've had similar situations, and what I've done is either:
1) Override the approval (click the checkbox) that will approve the ticket, and free up the ability to change the status.
2) Or in cases where that wasn't appropriate, I changed the request type to something that didn't have approvals, and then a little trash icon appears next to the approval in the ticket, and you can delete the approval requirement. Then I change the category back (although you may not need to do that step) and update the status.
If your situation is similar to mine, one of those two things should do the trick.