Hello @Seller_zvM16EQF2I9dN,

Thanks for reaching out and welcome to Amazon! Since you are new, you may find the New Seller group helpful. It's a safe space where you and other new sellers can ask each other questions, get help from some of our tenured sellers, as well as get help from the moderators.

Regarding updating your listing, you can't use an old discontinued ASIN and update it to a new product, you must create a new ASIN with a new UPC per the Detail Page Rules policy.

This is outlined in the section that states:

Policies for editing detail pages

You may only update detail pages to better or more accurately describe the product as originally listed. For example, permissible updates include additional details, clarifications, grammatical fixes, or removal of content that violates Amazon policy.

You may not update detail pages to repeatedly add and remove prohibited claims as identified in Amazon’s Prohibited product claims. Customers who are identified to repeatedly add and remove prohibited claims to circumvent this policy may be subjected to corrective actions, including but not limited to the immediate termination of selling privileges.

You may not repeatedly update your listing to add and remove prohibited images, disclaimers, or content to circumvent Amazon policy controls. Sellers must ensure their products are always accurately categorized, described, and in compliance with Amazon’s listing standards for any product sold on Amazon. Listing products on Amazon in a manner to avoid detection is considered evasive behavior. Evasive behavior does not have a path to reinstatement unless you provide valid proof of your adherence to all applicable laws and Amazon policies.

You must not use an existing listing for a new version of a product. This includes changes in color, size, material, features, and product name. Instead, create a new product detail page for each new version. For example, a manufacturer updates its streaming media player by adding a new remote control with four buttons instead of two. This product is materially different from the older version and it must be listed as a new ASIN.

If you choose to re-brand a product, refer to Amazon Brand Name Policy page for minor Brand name changes. Any major Brand Name change requests are considered re-branding and will not be supported. To protect Customer trust and ensure catalog quality, we ask that you create a new ASIN for the new product.

You cannot edit, update, or add the product ID for a listing that has been created with GTIN exemption. Product ID is a non-editable value and cannot be modified once a listing is created. If you want to update the product ID for a listing that has been created with GTIN exemption, you must delete and create a new listing of the product with a GS1 approved product identifier.

Once you create your new ASIN with a new UPC, you will then be able to put the items under the same variation. Please note that if you purchase a new UPC from GS1, it may take up to 14 days for the information to update in our system, so it may cause delays in you being able to create your listing. It doesn't always take that long, but just wanted to let you know in case you have issues.

I hope this is helpful!

Michelle