User story Description example by default needs to be changed

[Chetan Khanna]

Hi, 

I need to change a Description in user story, for example when we click on create a user story then window pop up, with all the required fields for us to create a user story, so by default when we go to description section it gives us an example such : As a (User type), I want ...... so that ..... so how i can change that as an admin ?  screenshot attached. i =wanted to add more there and delete some.