Oops!

Thanks for the correction, wuds! I was thinking I had done this sort of split recently, but now that you mention it...it probably was splitting of two pax. It was a two pax RT reservation (because of a coupon code), and when it became clear only one pax would take that trip I needed to free up the other funds.

ETA: Of course if the return flight is available at the same fare as was booked, the entire reservation could be canceled and some of the funds used to rebook the return as a OW.