Techniques can include: establishing a synchronous replication configuration for a group of stretched resources configured for bi-directional synchronous replication between a first site and a second site; and performing processing to implement a change or modification operation of the group of one or more existing stretched resources. The processing can include performing a three phase workflow comprising: a preparation phase that prepares the group for the change or modification operation of the group; a commitment phase that commits the change or modification operation to the group; and a synchronization phase that synchronizes content of the group in accordance with the change or modification operation to the group. Each stretched resource of the group can be configured from local resources of the first and second sites where such local resources have the same identity when exposed to an external host over paths from the first and second sites.