You can't request a preferred room, it's a bookable category. Well you CAN request one, but the odds are slim you'll get one. To get a refurbished room you best bet would be to make that your only request. Or as reports come in as to people getting refurbished rooms and where they were, you can request that location.
How do you request that with the online check in? I think we just had the option to check two options for requests. Is there a place to type a request? We requested Martinique, but we'd love a refurbished room!!