Thanks "dipulata"! I appreciate yr good / succint infos... And "Blyton", I've just seen yr message...

Well I hv not yet decided coz i hv realized that going to F1 from H1B is not so easy since one has to show proof of maintaining H1B status in terms of few recent paystubs and also it'll take atleast 6 months for USCIS/INS to notify if own's H1B-to-F1 case is approved or not.

If not approved, as "dipulata" has said, one's to leave USA in 1 month... So I'm not sure of any solutions yet!!!