I'm doing HNL-ITO-LAX-LAS this Saturday on UA (with a CO codeshare), but one of the friends that I booked on my PNR can no longer make it.

There were three of us going, so I already called UA and had them split the PNR so that the two of us that can go are on one and the one who can't go is on the other. (BTW, after splitting the PNR all my seats went from "confirmed" to "upgrade pending" woohoo! =)

Is there a way to suspend the ticket and then use it later when she decides she really wants to go to LAS?

Sorry for the very basic question, but I've never ever had to cancel a ticket before. I always follow through on my booked travel. I appreciate any suggestions/help you guys can give me.