How to resolve the error for "Alter Subscription disable"?
I figured out that the below functions will work:

     pctest1=&gt; select pglogical.alter_subscription_disable('sandbox_rds_pg10_subscriber');
-[ RECORD 1 ]--------------+--
alter_subscription_disable | t

pctest1=&gt; select * from pglogical.show_subscription_status();
-[ RECORD 1 ]-----+------------------------------------------------------------------------------------------
subscription_name | sandbox_rds_pg10_subscriber
status            | disabled
provider_node     | sandbox_provider
provider_dsn      | host=10.xx.xx.xx port=xxxx dbname=sandbox_uat user=admin password=xxxxxxxxxx
slot_name         | pgl_pctest1_sand2c004cb_sand98307b9
replication_sets  | {default}
forward_origins   | {all}

pctest1=&gt; select pglogical.alter_subscription_enable('sandbox_rds_pg10_subscriber');
-[ RECORD 1 ]-------------+--
alter_subscription_enable | t

pctest1=&gt; select * from pglogical.show_subscription_status();
-[ RECORD 1 ]-----+------------------------------------------------------------------------------------------
subscription_name | sandbox_rds_pg10_subscriber
status            | replicating
provider_node     | sandbox_provider
provider_dsn      | host=10.x.x.x port=xxxx dbname=sandbox_uat user=admin password=xxxxxxxx
slot_name         | pgl_pctest1_sand2c004cb_sand98307b9
replication_sets  | {default}
forward_origins   | {all}