I have multiple BrainStorm databases (research, phantoms, patients, removable drives, etc). Francois answered here the elegant way to politely detach, move, and import a database, maintaining your preferences.
I’m more impatient (grin).
A fast but not so elegant way to restart BrainStorm with a different database is to quit your brainstorm session, then, at the Matlab command line enter
brainstorm reset
which wipes out your customizations and database link (but only the link, the files are undisturbed).
Then move the database to a new server location, or (in my case) attach the disk drive with your other BrainStorm database you want to use.
Launch BrainStorm again, and this time, when asked by the initialization routines, open the root folder of your other database, and BrainStorm will attach and import your files.