Empty Cart
Select "Empty Cart" for when the Quick Reply is pressed. Why not a Button? Because it can be redundant to have more than one Empty Cart after all the products. Besides

Select "Empty Cart" for when the Quick Reply is pressed. Why not a Button? Because it can be redundant to have more than one Empty Cart after all the products. Besides, "Empty Cart" is in the Action step, and it is not a Button action. Therefore, you will need to select an Action step as the next step of the Quick Reply.