As long as there is no fancy stitching, and so forth on it you probably could hand wash it in WOOLITE! The big question would be, after it dries, will it be wrinkled up. One thing I like about my dryer is that it has a setting called "low Low" for items like that, I can just put them in a few minutes to help control wrinkles

You might also try washing it in a lingerie bag. They have some fairly large ones that should hold the dress with room to move around a bit. Don't put it in a full load - be sure it has room to move. As for drying, if the dress is quite wrinkled you can put in a few damp washcloths or microfiber towels and dry it on low. This can remove a lot of the wrinkles with less ironing.

I agree about not hanging, however you wash it you don't want to put that strain on it.

You need something like this Sweater Dryer so the garment is supported while it drives (not recommending this one particularly). Even a spreading on a bathtowel is better, though there would be lots of turning to get both sides dry.

=aw

NO!!!!!! Rayon is a synthetic fabric that mimics silk. It is this quality that gives it tremendous capacity for shrinkage when cleaned in water. It is close to impossible to stretch the fabric back into shape/size once it has shrunk because the fibers also tighten greatly.

If this is an expensive item, you're better of sending to the drycleaners.

Obviously not in a regular toploader or old style frontloader AND no-no-no in a regular dryer, but in a washer with a *true* wetclean/handwash cycle (for sure Bosch and Miele, guess also LG and Samsung).
Anyway read here

I wash Rayon mix on silk cycle all the time with my Miele...

never have any problem... ;)