Conversion of status from F1 to H1B (Start - October 2012)

I recently joined worked on OPT in the US after completing my Masters. My company applied for the H1-B in this years qouta, and it was approved to start from October 2012. Currently i am planning to come to India for a family function, in September 2012 and wanted to check if i could get the change in status from F1 to H1B, one month prior to the starting date on the H1B.

I would sincerely appreciate any information on this.