SilverChris

To answer my own question, and a data point which might of of use to some... no.

At YVR, was trying to SDC from YVR-YYC-YUL to a later YVR-YUL. Priority check-in agent was willing to do it as there was positive space, but system kept rejecting her changes. Got to YYC, tried SDC/stand-by for an earlier YYC-YUL, same response.

FWIW, on the return to YVR, OLCI offered standby, but I didn't use that option.

Bottom line is, don't count on SDC-ing on partner I/X awards. I recall having an easier time pre-Amadeus, not that it matters anymore.

Hope this helps