From the Altaro Offsite Server [Replication] screen, you'll be able to monitor all of your VMs that have been or are being replicated.

If you have a VM that doesn't need to be replicated any longer and you'd like to simply remove it from the Replication screen, after 24 hours of it failing the replica job, you'll get the option to [Delete] upon clicking on the wrench icon.

This will not delete the replicated data and will only remove the entry from the [Replication] screen. If you'd like to delete the replicated data, you can find the instructions in this article.