Hello, NonProfitMommaOf3. If the check hasn't been reconciled, simply go to the Bank Register, open the check, and select Delete. Since your vendor hasn't cashed it yet, removing the transaction won't create any discrepancies.
However, if the check is already reconciled, deleting it will affect your opening balance. To fix this, you can perform a mini reconciliation. This process is typically used when your QuickBooks balance doesn't match your statement after a transaction has been voided, deleted, or corrected.
Feel free to reply if you have further questions or additional concerns. I'm always here to help!