I need to void and reissue a check. The original was in a prior period, so I don't want to impact the AP balance, cash balance or expenses in the prior period.

Hello, @lsefcik.

I'll help you out in voiding the check without impacting the AP, cash, and expense balance in QuickBooks Online. 

The easiest way that I can think of right now is to enter a deposit in the current fiscal period for the same amount to the same account as the original check. Then after that, clear both (they will cancel each other out).

See the sample screenshot below for your reference: 

You can check these articles for more insights about reconciliation:

• Reconcile an account in QuickBooks Online
• Reconcile an account for multiple months or years of transactions and financial statements

Please know I'm always available here for all of your questions and concerns. Keep safe!

I guess this would work but I ended up creating a new invoice as of yesterday, paid it with a check as of yesterday, then voided the check and deleted the invoice.  That way, when the new check clears the bank it will match it to the original check and I will have everything balanced.  Of course I made notes in the memo section of everything so that it could be tracked.