Might want to rephrase this as I think you're missing the concept. Citi will probably let you combine/merge/close one account so you only have one in the end. Use the word that you want, but you'll end up with two line items on your credit report, one account reflected as 'closed by issuer' or 'closed by consumer' which are both negatives when Fair Isaac is involved.

Edit to add: It's better to leave an account open with no balance than to close it. When you pay your car off, the account is considered closed but Fair Isaac looks at these differently than credit cards.