A few months ago I bought a Jetblue "Blue" ticket to JFK on 10/31 for $120. Today Jetblue emails me a sale where that same ticket to JFK on 10/31 is $31.

Is there any way (*or trick)* where I can take advantage of this price even though I've already bought the ticket? 

I don't think cancelling is worth it because the fee would just eliminate any savings. Or am I wrong?