We would like to remove EBS volumes which were used for cold store and DM summary Docs is not overly clear on the recommended approach https://docs.splunk.com/Documentation/Splunk/7.3.4/Indexer/MigratetoSmartStore.
Here are the steps that could work for you.
Run “/opt/splunk/bin/splunk _internal call /services/cluster/master/control/control/init_recreate_index -method POST” on cluster master