Or just call the MVP Gold desk and cancel it over the phone. Just make sure you have a copy of the ticket number.
I tried a complicated workaround to canceling a similar ticket online (booked in my wife's name and purchased on my credit card), and it just complicated things further, requiring two phone calls to straighten out and one email.
My Wallet's cancellation procedure doesn't quite yet recognize the "ticket under control of MVPG" rule. But it may someday.
If you do it my way or COpltASgldPHX's way, you'll keep the entire value for your own later use.