What to do if there was a modification in total amount of a sale because of changes in the order

If an order is modified after the customer completed their purchase, you need to do the following:

1. Write the reason in Shopify of why you are charging them more then what their original order was. This can be done when you modify their order to send them a new invoice. Before you send the new invoice, you should see a field at the bottom of the page that says "reason for refund". After you fill this out, you can send your customer the new invoice.
2. In Pipedrive, find the deal of the customer and update the price
3. In the same deal, under "accounting notes" write down what modifications were made from the original order. EX: I refunded my customer $2 because they no longer wanted one leg extension.