Some states require you to have a state issued license to dispense controlled substances (ie, New Jersey requires you to have a CDS license in addition to your DEA).
If you list one state but then decide to move to another state, you have to notify the DEA of your change of address. If the new state doesn't require you to have an additional license, then there is nothing more to do. If it does, then of course you have to apply for that state's license as well.
Of the top of my head, I think its around 15 states or so which require the additional license.