There could be situations when it is necessary to move data from one instance to another or merge 2 instances together.
Currently as data encrypted using single key in instance:
It is not possible to migrate data anyway.
Only way is to manually export PGP keys from original instance and import it to destination clean one.
But this will mean that 2 instances will have same keys ....
Separating keys by Server ID for example or something similar could allow Admins to export and import data in such events.