The problem is going to be availability - there is probably little or none left for next week. 20 points is only 1 Friday night and 2 weeknights (No Saturday possibilities left after today)..
You can try posting on the rent/trade board, but even someone who already has a reservation may have trouble using them. MS will not just substitute holding account points for an existing reservation if there is a waitlist for the day(s) in question.
If it were me, I'd let them go - JMHO, but I don't think many members would want the hassle of trying to use them even if they cost only $4 or $5 a point.
Best wishes -