Hey there, @JeanLutzNA.

The steps provided by my colleague above are applicable in QuickBooks Online (QBO). I'd be glad to guide you on how to handle this in QuickBooks Desktop (QBDT).

For now, we're unable to delete an inventory adjustment in QBDT. As a workaround, you'll want to create a new adjustment to offset the duplicate entry. Then, you can add a memo to avoid confusion.

Here's how:

1. Go to the Vendors menu.
2. Select Inventory Activities and choose Adjust Quantity/Value on Hand.
3. Fill in the necessary information.
4. The QTY Difference should be negative if you're decreasing the quantity. Otherwise, it should be positive if it's an increase. 
5. Enter a note in the Memo field.
6. Select Save & Close.

Once done, you can take a look at your Inventory Valuation Detail report to make sure they are now correct.

1. Go to Reports and then Inventory.
2. Select the Inventory Valuation Detail report.
3. Look for the items you adjusted and make sure everything is correct.

Do let us know if you have any further questions. I'm always here to help. Take care.