take a look at  [URL] Basically you have to delete the replication session for this lun. expand the lun on both sides and then recreate the replication session
1. Can tell me do we need to pause or delete the replication first before expanding the volume? 2. Once the replication stop or delete, then do the lun expansion on both site, resume the replication? anyone can tell me the procedure?  
LUN expansion on 480F