We're traveling from Catania, Sicily to Istanbul this fall.

We're holding round trip tickets from Houston to Rome with layovers in Istanbul going and coming.

At the end of our trip, we're holding morning departure Ryan Air tickets from Catania in Sicily to Rome. Our intention is to catch the Rome to Istanbul TK flight (portion of our round trip booking) several hours after our arrival in Rome.

Now we've discovered that TK has a direct flight from Catania to IST that same day departing about the same time as our Ryan Air flight. If we could change the Rome->IST leg to the CTA->IST flight and blow off Ryan, we could save about 6 hours travel time.

I called TK customer service with this question and was told we'd have to pay an expensive change fee to pull this off. However, the customer service person didn't speak very good English.

My question is whether there is anyway to beat that change fee. For instance, could we stand-by for the Catania to IST flight and use the Rome to IST ticket (assuming the CTA to IST flight is lightly booked)?