Can magic bands be reassigned?

[Robo]

Ok, we have bands from a previous trip. Can we re-use the same bands, and just reload our new trip in October?

And to be more directly clear, nothing is ever loaded onto a MB.
The MB simply contains a permanent code number that “calls up” your unique MyDisneyExpress file of information. So when you buy new tickets or book another WDW room (etc.) that info can be put into your MDX and that info is automatically referenced in your file when you scan any of your MBs.
The MB is like a key to unlock your info.