If you’ve imported a pool from another system and want to change the name or have just changed your mind, this is actually quite straightforward to do. Run the following (as root):
zpool export [poolname]
As an example, for a pool named tank which we wish to rename notankshere:
zpool export tank
zpool import [poolname] [newpoolname]
zpool import tank notankshere
The pool will be imported as “notankshere” instead.