Are they this year's allotment or last year's?
I book my husband's buddy passes just before they expire, using the buddy's CC, address, DOB, etc with a nearby destination. Then they are good for another year--al travel must be completed just short of his next year anniversary.
If they want to go somewhere besides the original dest, they pay the $25 fee (beyond 100 miles) and the mileage cost difference.
So, my niece is using BP that would have exp'd in July. We booked her SFO/SLC, even tho her planned idea is to travel to Santiago, Chile next spring. She is eligible to complete travel to anywhere on DL metal within one year. I typically make the change just prior to BP travel.

If we need to use current year passes for anyone, they re still intact for this year; or next year IF I assign them. If not assigned they go KAPUT! They are fully refundable until the expiry.