MIP- Can I change the VariationSpecifics on an existing SKU?
Revising VariationSpecifics (Trait Names or Trait Values) for a SKU
MIP does not allow a Merchant to change the VariationSpecifics on an existing SKU.
The Merchant must either:
Create a new SKU with the updated VariationSpecifics & set the Quantity=0 on the old SKU.
Con: The old SKU will show as Out of Stock vs. being removed completely (see screenshot below)
or Delete the Product that the SKU belongs to via a Purge feed and re-submit through a later Product Feed.
Con: Despite only one of the SKUs being botched, you must end the entire Product/Listing and lose all sales history.
Short Answer: Trading API & eBay
A Variation SKU cannot be deleted if it has been sold one or more times (Trading API Error)
Because you cannot delete it, you can only set the Quantity to 0.
Even after setting the Quantity to 0, you still cannot change the VariationSpecifics (Trading API Error Code 21916585)
Advanced Answer/History: Once a SKU has had a sale, that SKU is bound to the VariationSpecifics for life (until the entire MSKU Listing is ended explicitly or all Variations sellout).
Re-worded for emphasis: You cannot re-use a SKU for a Variation if it has been used to represent a different Variation before.
Even upon a Relist, you cannot re-purpose a SKU that was used before and had a sale unless you specifically delete it.
Example: If you had a SKU "PinkS" that corresponded to Color="Pnik" (sic) and Size="S" and it sold at least once, you cannot end and re-list and add a new Variation with Color="Pink" and Size="S" with a SKU label of "PinkS" unless you send <Delete>true</Delete> as seen below:
In MIP, a Variation is deleted via the Item.Variations.Variation[i].Delete tag.
Instead, when Quantity is provided as 0, the Item.Variations.Variation[i].Quantity tag is set to 0.
Using Delete as a means of conveying Quantity=0 doesn't work because you cannot Delete a Variation if it has had a sale.
When a Quantity is set to 0, ViewItem shows this particular Variation to be Out Of Stock.
Note that if the Delete tag were programmatically feasible, it removes the option from the dropdowns altogether!
If a Merchant has a Product with Variations, and quite a few of these Variations are permanently out of stock (will never come back), it might be in their best interest to end the listing and re-add it. Why? It's an annoying user experience when you're offering say, a Color combination for a Shirt that will never come back in stock, yet ViewItem might be hinting it could be re-stocked soon.