Can the PNR be split into the 2 who will travel and then the 1 who won't? Then cancel/try to refund the 1 ticket PNR who can't make the trip so you don't risk them mucking up the PNR for the 2 still traveling? I know I see people recommending splitting PNRs all the time for medallion upgrade chances.

Just brainstorming here, far outside my own realm of experience. Thanks!