It's cheaper for me to buy a return ticket but my return (inbound) date is not 100% firm. Looking at the business comfort fare where it says you have flexibility to make 2 changes.

I imagine a fare difference will apply for date changes if the ticket has not been flown (if not what is stopping someone from booking a cheaper date and immediately changing it to another one) but how about for a partially flown ticket? Would I have flexibility to change the inbound date after flying the outbound segment as long as the business comfort fare is available?