Originally Posted by
flyerCO
Can you book later flight with miles?. Just because can book it with cash doesn't mean can book with miles. Advance schedule changes for awards on partner operated metal requires the partner have space for awards on new flight. If this was DL metal they could override.
These are good points too. I had assumed "brand new set of 3x tickets" was still referring to using miles, but on rereading OP didn't actually say.