Last year I was supposed to go to the FLL Do but had to cancel due to family problem. I canceled before the outbound flight, and was told I'd have 'x' residual to use for a future flight after change fee for flight in the next year.

Never having been in this situation before:

a) What are the odds of getting the change fee to be the old $100 since the cancel was done before the new $150 fee went into effect? That's not a major issue, but $50 is $50.

b) The more important part - do I have to fly by the end of Oct (which is when the trip was originally scheduled for) or do I just have to book by the end of Oct & can fly later? Reason I ask is that if it's the latter then I'll book before end of Oct for Xmas visit to my sister. If it's the former, then I need to book/fly before then so I don't lose the ticket value.

Any input appreciated. Cheers.