How can I add, change or remove Deal Statuses?

You can add, change and/or remove pre-defined Deal Statuses from the Settings page.  Click on the Settings (cog wheel) icon:  

Click on the Deal Status icon to be taken to the Deal Status settings page:   From the Deal Status settings page, you can add, change or delete Deal Statuses.

When you add or change a Deal Status, you can set a status color for each Deal Stage. For example, you can use Green in the Lead stage and Green in the Application stage. When creating a new Deal Status, it must be tied to a Deal Stage. 

Refer to this article for more info about Deal Statuses, including how they are associated with Stages.