Immediately retracting a draw offer

So my analasyis skills clearly aren't up to scratch; I'm playing a game with a really close endgame position and where we're both down to our last few pieces with little hope for either side.  I offered a draw, then immediately noticed a way to win the game; however there doesn't appear to be a way to retract the draw offer?  I'm not set to 'touch-move' rules, so surely there must be some way to retract the draw offer instead of just hoping my opponent doesn't accept it?  

Any help?  Am I missing something here, or is there no way to do this?

Just like OTB, "touch move" has nothing to do with offering a draw. If OTB you don't touch anything, but offer a draw, your opponent can accept it if they want. A draw offer once made cannot be retracted.