Originally Posted by
ftnoob
As nsx said, you'll be fine if you no show. If you want to be considerate, however, or want to reuse the funds without waiting for them to become available several days after the return, there is another option. Have CS&S split the reservation. They'll give you the new PNR; you'll also receive an Email confirmation with the new PNR. Then cancel or change the new unwanted outbound reservation.
multiple pax res can be split with each divided pax assigned a new pnr but a round trip single pax pnr cannot be split this way. individual segments may be cancelled by cs&s, which is what will be done for the op's situation.