This is not an option in the current Unraid releases as you cannot move files between pools - only to/from a pool and the main Unraid array.
it is likely that this restriction will disappear in the Unraid 6.13 release where we have been told that the current Unraid array becomes just another pool type, but there is no ETA when this will be available, and there is always the chance that things do not turn out as expected.