Yes you can.
I sold some from SW to see because I had the same thought and this was after the DEM(MEPEX) shares were allocated into my acc. My tally on the ASX letters that I have don't match my holdings in my account because I ran this test. Its a stupid system where you can accept the offer on one hand and all the paperwork in the background gets done then I can simply push a few buttons and pull those back. The accepted shares should sit in a ADN trust account and not be tradable IMO. I doubt there's many traders trying to flip the pip but as I said I ran a trial and it worked for my holdings but I'm not sure if it would work for other brokers. This is only going to drag out the process IMO unless a broker for the deal has the vac out.
MEP Price at posting:
20.5¢ Sentiment: Buy Disclosure: Held