How do I get rid of a check on a clients account that the client stopped payment on?

Hello there, @bwoehle.

Thanks for reaching out to us. I'm here to help on how to remove a check in your QuickBooks Online.

In this case, what you need to do is delete the check you've sent for your client. To do this, here's how: 

1. From the left menu, select Sales.
2. Choose All Sales.
3. Find the check transaction.
4. Select More, then choose Void or Delete. 
5. Click Yes to confirm voiding or deleting transactions. 

For additional reference, you can check this article: How to void or delete an invoice or other transactions.

This will get you on the right track! Don't hesitate to leave a comment below if you have any other questions about check. I'm always here to help. Have a good one.