how to change crystal frequency for MCU

Hi Guys,
there is any provision so i can change crystal frequency via Arduino IDE??
in my case
i have mega ADK in that board crystal was damaged and i am not good in soldering

if i change fuse bit of Atmega2560 use internal crystal so there is no need of external crystal in this case my ADK board working fine ?? even USB
for this method would i change crystal frequency by IDE if yes so how could i do this??

Any other suggestion??

Thanks in Advance

Use a if define / undefine / define sequence.

You can but try it. The internal oscillator is not a crystal, its an RC oscillator and isn't as stable and I think its 8MHz. You will need to use the
right board setting (which probably means creating a new entry in boards.txt with the right clock frequency - you would clone
the existing Mega2560 entry and rename it and change the one line that defines the clock).