If you have a receipt, Costco should honor it's return policy regardless if you are a member it not. Just call and check with them
I agree, need receipt or be member.
It really depends on the store. If you have the name of the person who bought it, they can pull it up without a receipt. Everything that's bought by a member is stored on their account, so receipts aren't usually needed, but in your case would help. I would call ahead and ask before going in.
It is my believe you either need a receipt or be a member.
Thanks! Your answer is awaiting moderation.