How do I change the address to access email to something other than example.com/webmail?

I've scoured both the Inmotion site and the interwebs in general, but I haven't found a simple to follow answer.

How can I change the default example.com/webmail address to access email to something else? That something else could be example.com/somethingelse or maybe somethingelse.example.com.

Thanks in advance!