The new version of managed inventory is too difficult to use, can Amazon change back to the old version

Advice needed - I am discontinuing one version of a private brand product and will be listing a new and improved version, different ASIN and UPC. Old version is currently listed as active but with 0 inventory. How do I refer one to another? If I delete the old listing, I'll lose all my reviews and ratings. These are currently fulfilled FBM. Thoughts?

I have merchandise that my customers have returned in like-new condition but the unit carton packaging has been damaged and the bar code has the LPN label over it.

I'd like to resell these items as FBM at a discount. When I copy my FBA listing to create a new product that I ship FBM and use the existing UPC product ID, the "offer condition type" is locked out as "new."

Options:

1. Sell as new with a note regarding the condition of the unit carton,

2. Sell as "don't have external product ID" (or something like that) an label as "used."

Any suggestions?