I need to assign a specific task to another group member every time a lead is completed.

I need to assign a specific task to another group member every time a lead is completed. In the task section, it displays the task 'Hand off to Concierge,' but I need to see the options available for the concierge. However, I can't find this option. It only appears as a checkbox, but I am unable to assign it to a Copper user.