This feature is available in Catalyst, Enterprise, and Ultimate editions.
List Values are the options that display in drop-down menu lists throughout the system. Follow the instructions in this article to remove a value from a drop-down menu list.
How to Delete a List Type Value
List Type Administration functions are only available to users with an Admin Privileges role of "System Administrator".
Select Admin > List Types.
Select a List Type tab (Task, Test, Story/Backlog Item, etc.), and then navigate to the desired List Name section.
Click the arrow next to the Edit button, and then select Delete.