I just earned a companion pass (thru 12/31/2018), and will designate my daughter as my companion. But prior to earning the CP, I had already booked and paid for three flights (either with $ or points) for her with the two of us flying together. Assuming there is availability of seats, can I cancel those flights for her (and get my points back and/or credit), and rebook my daughter using the CP?
Yes. If you purchased Wanna Get Away fare tickets for your daughter you will get travel funds that she can use for flights within one year of the original purchase. You can use those funds to pay the taxes on the Companion Pass flights or for tickets if she flies without you. Points will be refunded to your account.