Yes, it looks like you can donate less than a whole ticket
Originally Posted by Billiken
Is there a way to donate miles LESS than the amount required for a Y ticket?
I'd be happy to let them have my wife's DL miles which expire 31-Dec.
However, there amount is far below what's required for a free ticket.
Looks like
www.heromiles.org will accept whatever miles you have on several airlines.