Tiffany's services for second-hand Tiffany ring?

[el_loco]

If I buy a Tiffany ring on Ebay or second-hand with the certificate and a "retail valuation", can I get it re-sized, clean/polish, and/or repair at Tiffanys (paying the corresponding fees)? Or do I need to be the original buyer?
Also, Can I get a new "retail valuation" from Tiffany?

Please help!!!

 

[Sooie]

They did for me in Scottsdale, AZ. We walked right in and told them where we got it. Salesperson was totally cool. They authenticated it and sent it to NY for resizing for a small fee. I don't know if that would be the case everywhere tho. You could always say it was inherited or gifted to you...?