Can H1B Start date be postponed after approval date??

I am on L1B visa,My H1B is in process, I have got RFE. If my employer replies back to RFE within next few days, Can I get the start date for H1B changed to start it from 1st Jan 2013 as I want my H1B to start from January as market is good in January. Is it possible to request USCIS to change the start date of the Visa after approval or befoe approval.

I don’t think it is possible.