How would I go about getting a portion of a wedding dress dyed?

Like how Gwen Stefani had the bottom of her dress dyed pink: a href="http://www.moissaniteco.com/round-brilliant-moissanite-6prong-trellis-engagement-ring-p-9778.html" rel="nofollow"http://www.moissaniteco.com/round-brilli…/a