Switch into and out from New Tax regime

Dear All,

I would like to know whether an income tax assessee can switch to and fro between old and new tax regimes, every year? Also would like to know whether he/she can opt for one tax regime in the beginning of the financial year and switch over to the other regime at the time of e filing which usually would happen in the subsequent FY? And when should he/she inform the choice to either auditors or to the employers? Will be damn happy to get your esteemed opinions and guidance in these matters.

Thanks and Take Care

Yours

K. Suresh