Hi there, @Becky2019.

Disabling the pricing rule will affect all the sales orders associated with it. Before disabling this feature, you'll want to ensure there are no other transactions linked with the rule to avoid any issues.

 
To disable the Pricing Rule, you can follow these easy steps below:

1. Open your QuickBooks Desktop (QBDT).
2. Go to the Lists menu.
3. Select the Price Rule List.
4. Click the price rule you want to delete.
5. Select the Price Rule drop-down and click Delete Price Rule.
6. Click OK.

You can also check this article and read the Make a price rule inactive section for more information and detailed steps.

I'm also adding this article for future reference. This link can guide you through the process on removing a credit from an invoice: Remove or unapply a credit from an invoice or bill.

Let me know in the comment section if there's anything else I can help you with. I'll be around to help. Keep safe and stay healthy.