To delete the token, you can either right click on the token in the response window and select "Remove Token" or click on the token in the response window to give it focus and hit the delete key. You can also start from scratch and delete all the tokens in the block by selecting "Clear Parsing".
You cannot delete the token from the Outputs list, you must delete it from the response window in the right hand view of the Assistant.
I hope this helps.
-Tommy