There is unfortunately no easy way.
The process will be similar to MSDP Storage Server name change as per this section of the Dedupe Guide:
The steps will be the same - just skip steps 7 and 8.
There was a similar question w.r.t Quantum OST over here:
This user simply created a new Storage Server and left the old one to expire images naturally.
Just not sure how good this will work in the long run when images need to be expired and media server nbdelete command needs to connect to the Storage Server for image deletion and cleanup.