I booked a flight on AA with BA miles.
But then I wasn't able to get my other legs on AA, and I ended up booking the whole trip with CO miles.
So I called BA and asked them to undo the ticket. They said the office was closed, but it would cost $70 to get the points back.
Meanwhile, I got an email from BA, saying that they needed my name, birthdate, and gender to complete the booking.
So I emailed back and said: actually, can you cancel the ticket.
So she did, with no fee.
Ha ha ha.
(If you are wondering, I am flying from ORD to SLC on first class, From SLC to JFK on first class, and From LGA to ORD on economy, for 47500 CO points plus $85. Booked one week before, and during spring break. SLC is a big spring break destination.)