How do you increase a Customer Invoice in a previous fiscal period without affecting the already finalized financials?

Hi there, 

It's important you're able to increase the customer invoice in a previous fiscal period. I'd be glad to point you towards the right direction. 

Based on your description, it sounds like the invoice is from a period that was reconciled. If you'd like to edit a reconciled transaction you'll have to unreconcile the transaction first. Don't worry, I'll show you how to do this. 

Here's how to unreconcile in QuickBooks:

   1. Select the Gear icon on the Toolbar.
   2. Under Your Company, select Chart of Accounts.
   3. Locate the appropriate account for the transaction.
   4. From the Action column, select Account History.
   5. Identify the transaction to edit.
   6. In the reconcile status column (indicated by a check mark), repeatedly select the top line of the transaction to change the status of the transaction.

        Codes indicate the status of the transaction:
             C - Cleared
             R - Reconciled
             Blank - Not cleared or reconciled

   7. Select Save.
 

For additional tips on how to avoid undoing a reconciliation, take a look at this article: Avoid undoing a reconciliation. To see a more in-depth explanation of how to manually undo a reconciliation without an accountant, check out this article: How to unreconcile a transaction or undo a reconciliation.

Once you've reconciled, you'll be able to edit the transaction in question. 

Let me know if you have other questions. I'll be on standby.