First, the change fee is $100, since you booked before they upped it to $150. Check your original receipt for details, and don't let an ignorant agent tell you otherwise.

Second, you could hope for a CO schedule change rendering the itinerary unworkable. However, FLL-IAH and IAH-SNA are fairly common flights, and I doubt you'd find a significant enough schedule change.

If you don't intend on flying CO for your trip, you don't have to cancel right away -- you can wait until it gets closer to see if you get a schedule change.