If you want to run multiple workflows, remotely on a robot, you can either mark one of the workflows as a background workflow, or you can update settings.json to allow running multiple workflows, by setting remote_allow_multiple_running to true and remote_allow_multiple_running_max to the max number of workflows.
But that is not recommended. If you need to keep state, or if you need to run multiple workflows at the same time, you should look into using workitem queues.