Sh.Fenil Sanghvi Ji,
In your case PAN will be changed. If PAN is changed new registration no. will be issued. Go through Point No. 9 & 10 of Notification No.7/15-CE(NT) dated 1.3.15 which is appended below:-
(9) Transfer of Business or acquisition of factory : Where a registered person transfers his business to another person, the transferee shall get himself registered afresh. Where an applicant has acquired an old factory from a Bank or a Financial Institution, he shall get himself registered afresh.
(10) Change in the Constitution : Where a registered person is a firm or a company or association of persons, then in the event of any change in the constitution of the firm leading to change in PAN, he shall get himself registered afresh. In other cases of change in constitution of business, where there is no change in PAN, the same shall be intimated to the jurisdictional Central Excise Officer within thirty days of such change by way of amendment to the registration details to be carried out online in website www.aces.gov.in and this will not result in any change in the registration number.
Further first clear all the goods and bring the stock to NIL and, thereafter, apply for afresh registration. This is the best way.