To Dye or Not to Dye

[zagethe]

I was hoping someone could offer some suggestions... I purchased a wonderful, long, floor length dress (I assume it was a dress tho it does open all the way in the front). I bought it to be a coat. It has gold military trim including the military style buttons all down the front and a mandarin collar with eplets... the problem? The dress/coat is RED. While it does look stunning to see the red and gold I'm just not that brave and would like to dye it. I'm concerned about how red fabric dyes. It is a true red and while black was my first "go to" color.. I have/wear so much of it I thought about brown instead but this is a true red and I'm wondering if the dye will cover. Obviously, I couldn't go lighter but any thoughts? Anyone ever try to dye red clothing to another color? The fabric seems to be a smooth polyester, light to medium weight with a slight sheen.

Help?