It is possible to "get lucky" when changing agents, Ganesh. Of course, some agents are better than others, but they're all chasing the same market.
It's rather like going to auction. You can't just "force" a sale. There is still a large pool of potential buyers out there, but they're unable to raise the cash, or not prepared to under current lending restrictions/fees etc.
If the 6 months is the case, then take it off now. Forget about it, and start again sometime next Spring. In the interim, do your research until you come up with an agent you fancy.
Good luck