Perhaps you've been there yourself. You've served in the reserves but need to make a move that will far remove you from your drilling location. Reservists who move beyond a “reasonable” distance from their training units cannot be punished for not attending drills, contrary to what some members hear from their commands. Callers to the GI Rights Hotline report threats of unexcused absences and even attempts by their command to chapter them out of the reserves for unsatisfactory participation. Such measures, while intimidating, are not backed by the regulations and can be successfully challenged.
You do have the responsibility to promply notify your command of a change in address especially when that change moves you outside of the maximum commuting distance.
Enslosure 3 of DOD Instruction 1215.13 mandates that the maximum distance a reservist can be required to travel to an IDT (training) site is 100 miles or three hours under normal driving conditions, assuming meals and quarters are provided. Without meals and quarters, the maximum distance is 50 miles and travel time 1.5 hours.
If you move beyond this reasonable commuting distance, you have several options, none of which include punitive action. Your unit is supposed to transfer you to a new paid-drill unit of the same RC within commuting distance of your new address or give you 90 days to find a new unit. After 95 days, it is mandatory that you be transferred to the IRR. If you wish (they cannot force you), you may also request retention on the rolls of your current unit, assignment to a vacancy with a new specialty that requires additional training, or transfer to a new RC.
Reservists who are planning on moving may want to discuss these options with their command ahead of time, making sure to communicate that you understand your right not to be required to attend drills beyond the commuting distance. Having a copy of the regulation at the discussion can help prevent misinformation. Each military branch has their own regulation specifiying appropriate action (see your branch's link in the boxes titled "Absences (Reserves)" at Resources).
If your command attempts to undertake punitive action, you can call the GI Rights Hotline and we will happily assist you in asserting your rights.