Karl referenced correctly, but will explain bit more here.  If this is A->B and A->C (one to many), by reversing the replication on A->B, the new setup will become cascaded (B->A->C)  To convert to one to many to cascade, ensure first, nas_refresh -refresh works good from A->B and A->C and finishes with no issues. Once it is good, you can issue, nas_replicate -reverse from A to convert to cascaded.  Once you got like that above, you push the commonbase ckpt like Karl referenced, which you can do like:  1) Create B-C interconnects 2) Create the ckpt on B (the new source) -> fs_ckpt fsname -name fs_cb_ckpt 3) From B to A session ->  nas_replicate -refresh fs1_BtoA_rep -source fs_cb_ckpt -destination fs_cb_ckpt 4) Once above sync finishes, then issue on A -> nas_replicate -refresh fs1_AtoC_rep -source fs_cb_ckpt -destination fs_cb_ckpt 5) when the above finishes, you can delete the replications from A-C first 6) create new rep from B to C like (this will do the incremental copy) : nas_replicate -create fs1_BtoC -name sourcefs -destination destfs -vdm ifany -interconnect BtoC_interconnect -overwrite_destination  7) Delete B-A session    
Hello, We have a current replication session from site A to site B and A to site C, I need to switch-over to site B because site A will be going away so the question is, can we replicate from B to C maintaining the current data on C, or do I have to re-sync B to C from scratch?  Any help is much appreciated.
NAS replication to multiple sites.