ALTER DATABASE DROP REPLICA

Drop a replica object from a source system.

ALTER DATABASE local_database_name DROP REPLICA replica_name

When you drop a replica, its corresponding backup chain is also dropped.

For example:
premdb=# alter database premdb drop replica premdb_replica;
DROP REPLICA
In this example, the replica cannot be dropped because replication is in progress:
premdb=# alter database premdb drop replica premdb_replica;
ERROR:  Failed to drop replica
DETAIL:  Cannot drop replica premdb_replica from database premdb because it is currently running
In order to drop this replica, you have to pause replication first:
premdb=# alter database premdb alter replica premdb_replica pause;
PAUSE REPLICA
premdb=# alter database premdb drop replica premdb_replica;
DROP REPLICA