The frequency 72.830 is referred to as channel 52. You can remove that crystal and replace it with another, but why do you want to do that? You're obviusly new to RC, so I'm guessing you just got this airplane Ready to Fly. Didn't it come with the Transmitter and Receiver? If so, then they should be on the same frequency.

If you change drystals, use one from the same manufacturer. A crystal from one company won't always work in another's receiver.

If it's Futaba, you'll also need to keep the new channel on the high end of those available.
Dennis-