To drop a replication group, use the following command:

./bin/yugabyted xcluster delete_replication \
    --replication_id <replication_id> \
    --target_address <ip_of_any_target_cluster_node>

To drop a replication group, use the following command:

./bin/yb-admin \
-master_addresses <primary_master_addresses> \
drop_xcluster_replication <replication_group_id> <standby_master_addresses>

You should see output similar to the following:

Outbound xCluster Replication group rg1 deleted successfully