I have a Storage Unit (Repository of Backup on site A)  I replicate this one with Mtree replication to another DD (Site B) 

StorageUnit1-SitA --> StorageUnit1-SitB

I would like performing a test of DR

I Break the relation 

My destination StorageUnit1-SitB pass to  RW 

I launch new backup on this Storage Unit and then I would like Inverse relation

StorageUnit1-SitB --> StorageUnit1-->sitA 

How perform this inversion without destroy Mtree and then recreate