Yes, but check the taxes and YQ since you booked, you might get a nasty shock, the ICC are not very transparent with this on changes. I'd suggest you checked it on ITA yourself first and ideally ask for a new price for the itinerary before getting a price to change. Don't let the agent release your existing seats till you have a price to change! And this is why...

Just before Christmas seats came available on an additional flight from LIR rather than our original SJO, on our trip back from Costa Rica to UK. Great I thought CO, flat bed from IAH, no overnight in CLT, original routing was on US.

The agent released the seats and recalced the taxes on a one way home, I knew it would be more with YQ on CO but, it was an extra £350 per pax...... The original seats had gone and weren't there no more.. Anyway taxes rechecked, supervisor insisted it was correct, despite my suspicion that original taxes weren't being deducted.

Now I pleaded/argued that the seats shouldn't have been released till I knew the new price. Eventually, as a concession I paid just the change fee and in hindsight consider myself quite fortunate.