Thanks Wanda,

you are completely right, I was checked this approach a day after my
question. For all other here, the correct way is:
1. Export archive node data (EXPORT NODE ... FILEDATA=ARCHIVE)
2. Delete archive data (by DELETE FILESPACE or by client GUI)
3. Change management class for archives (archive copy group) to point to new
tape pool
4. Import node data (IMPORT NODE)

Archive data will be imported to new pool regarding to set of management
class for given node.

Thanks to your help
Tom