I got an aqua blue 3ds for my birthday and I thought the color was cool. But since the red one came out, I started to have second thoughts about the color. So anyways, I heard about the Cobalt blue 3ds coming out soon and I was wondering if I can trade my 3ds for the Cobalt blue one ( when it comes out).
There isn't any current way to trade in for another color. Don't try to exchange one at a store, because then none of your downloaded games or data will be transferred.
You could possibly send in your 3DS for a repair, and if there was enough damage to warrant a full replacement, you could request a certain color. However, this sort of thing would require a lot of damage that your 3DS doesn't have.
I suggest that you stick with your color. From time to time, I think to myself that a different color, especially the red and Zelda limited edition 3DS, would look nicer. Even with a new color, you will quickly get used to that one and it won't seem as special.
In addition to what MACHBIKER stated, the Cobalt Blue Nintendo 3DS handheld system has only been announced for release in Japan. Neither Nintendo of America nor Nintendo of Europe have confirmed that the Cobalt Blue Nintendo 3DS handheld system will be released in their respective regions.