Users are able to create custom 1:1 templates that can be applied to 1:1 relationships. However, sometimes you may no longer need a template and thus wish to delete it. Here are the instructions to do so:
Select 1:1s > All 1:1s.
Select Manage Templates.
Select the ellipsis (...) > Select Delete.
In the confirmation screen select Yes, delete to confirm.
Note: This is a permanent and irreversible process.