The credit card holder making the purchase must be a traveling passenger or have the same last name of at least one passenger. Yes, you must cancel the reservation. There may be a cancellation fee or you may receive a refund for the unused ticket depending on the applicable fare rules. I have a friend that is traveling on the same flight with me and I need to change my seat assignment. You can change your seat online if your SkyMiles account number has been entered into your reservation.
Delta accommodates the seating requirements of customers with certain types of disabilities.
This could result in the occasional need to change another individual's pre-assigned seat, with bulkhead seats being particularly subject to reassignment. We appreciate your cooperation in these special circumstances.