How do I allow Hosts to turn Listings on/off without deleting them?

You can allow your vendors to enable or un-enable their Listings by simply adding the attribute  Transactable - Enabled to your Transactable Attribute (secondary listing) forms.

To do this, go to  Admin Dash > Manage > Service Types > Form Components > (choose a transactable attribute form) and check the box for the attribute Transactable - Enabled

Your Hosts will now see this option when editing or creating Listings: