How to Cancel a Keyword
Keywords are like domain names, once you rent them you cannot tweak them. However, you can delete a keyword and change it to a different one.
To cancel a Keyword click Keywords in the left panel.
Click the three horizontal dots (the "meatball" menu) to the far right of the Keyword. A dropdown menu will appear. Click "Delete Keyword." This will delete your current keyword making it possible for you to add a new one.
Click here to learn how you can add a new keyword.