No. In Process means that your customer has made the payment and the money is on its way to you, so you won’t be able to delete the invoice in Get Paid.  

Fincent is linked directly to your QuickBooks Online (QBO) account. If you do delete the invoice from QBO, we will continue to process your customer’s payment, and the details of the deleted invoice will still show on Fincent. Your customer will continue to see the invoice details on their payment confirmation page. We will let you know that the invoice has been deleted from QBO. 

Note: You must be a Fincent user on the Starting, Growing, or Thriving plan to edit or manage invoices.