In the US it is illegal to change the transmitter crystal. Most radios are specifically tuned for whatever channel they are on. You can change the crystal but range could suffer.

You can either buy a new one on the channel you want or send it back to Futaba and have them change it which would be the cheaper of the 2 options and would guarentee the radio be tuned correctly.

For the legal and just as important, safety reasons, I would not change the transmitter crystal on my own.