Walmart does not delete old listings, it just archives them. So, if you create a listing with a new SKU but the same UPC as an old listing, this can lead to Walmart throwing an error.
The Flip SKU integration setting on LM automatically changes the marketplace SKU if the UPC matches a SKU already existing on Walmart. It changes the newest incoming SKU to the existing marketplace SKU with the same UPC. This can help you avoid errors while pushing out Walmart listings.
Here's how to turn this setting on:
1. Go to Integration>Channel Integrations.
2. Select the Edit icon for your Walmart channel:
3. On the Advanced tab of your Walmart integration settings, you should see the Flip SKUs option.
If you can't check this box, contact Support at Listing Mirror and we can turn this on for you.