Dream, all "they" have to do is the same as you or I--enter a code at the SIM card screen on the BB.
Likewise, as Dream said, it should NOT be a big deal or problem. But you asked the question so I answered it...
Whoozer--If you don't have SEND on your menu, you may not have a service book for your mail setup. Since you don't provide much detail of your problem--Have you sent mail before?
For now, pull the battery and reboot and see if that brings your service book back, it could. If not , post again for other suggestions.
If you need to send your service books, read here: How do I resend my service books? - BlackBerryFAQ