I want to capture the payment process and modify the total accordingly. For instance, let's just say the user swipes his/her credit card, I want to get a callback regarding the auth etc.
If Clover processes an order, you can't get access to modify the authorization, you should use the "Custom Tenders" and then continue the flow of payment. Basically do the modification first. Clover will not provide details on the transaction beyond the scope of basic information.
More on Custom Tenders Here
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