We have an employee heading out Tuesday to JNB, utilizing an AC/SA joint-fare, YUL/NYC/JNB on the outbound. Usually he takes the first flight out ex YUL for LGA, but Tuesday AM this flight was full...and thus he was placed on the first AM for EWR...still considered a legal connection over to JFK, but...

Was wondering what his chances might be, when he checks in at YUL, if he explains the situation to the AC agent, whether they might be amenable to placing him on the LGA flight, if there remains space (i.e. the reason he isn't on it to begin with is that the thru-fare had to be booked in Q-class inventory, so, while flight had space to sell, it wasn't open in Q), if he explains the inter-airport connection scenario and how it would be more convenient to go to LGA than EWR....and why it was booked this way to begin with....

Perhaps he might find an understanding agent...since EWR/LGA are interchangeable airports, although they may be less willing since it is that joint fare issued on SA stock...