How do you reclassify your MOS?

Answer 1

Which component you're in could make a difference here. Within the timeframe of your enlistment contract, it can be done in the reserve components, but the only options for active soldiers are 1: reenlist for a new MOS, 2: reclassify through the BEAR programme (for occupations such as EOD), or 3: complete SFAS and the Q-Course, for which you'll be awarded an 18 series (Special Forces) MOS.

Note that, just because it's possible to do in a reserve component, doesn't mean you'll be allowed to do it on a whim. You would need a valid reason, e.g., you're moving elsewhere, and no unit within within reasonable distance of your new location has slots for your MOS.