If you try to modify a variation listing, or if you try to convert a single listing to a variation listing, eBay will throw an error. This article will tell you the consequences of the two options you can use to fix this issue.
1. End and Relist: The most common fix to this is to do an End And Relist.
The need for an End and Relist arises because you added a variation to an existing variation listing, which eBay does not allow. eBay has strict timing regulations about modifications to variation listings, and this is not something that Listing Mirror controls. eBay has strict rules regarding adding variations to an existing marketplace listing in a timely manner using the API. The time window that they have set in place is once you have the initial listing posted, you have 5 minutes to add the first variation, then 5 minutes to add the next variation, etc.
If you use this option, you will lose Sales History.
2. Delete and Reimport: However, if you are worried about losing Sales History, you may want to do a Delete & Reimport Action.
When you do this, the listing will import back into Listing Mirror exactly as it is on eBay or Shopify. This may mean that the changes you made to the listing on LM that caused the error or warning message to come up(modifying variation details or adding a variation) will not be pushed to eBay. If you want the changes to be pushed to eBay, you will have to do an End and Relist.
Now that you know the consequences of the two options you have to correct this issue, you can make an informed decision on which option you would like to use.