Solved! Go to Solution.
Right-Click on the Child Geodatabases's connection (Sa_S2.sde)--> Distributed Geodatabase-->Manage Replicas--> check whether a Replica with the same name already exists there!
[ATTACH=CONFIG]21390[/ATTACH]
If there is a Replica already present with the same name--> Unregister the replica and then try creating the new Replica...
Regards,