i.) A person already registered under any of the existing laws (Central excise, Service tax, VAT etc.), but who now is not liable to be registered under the GST Act has to submit an application electronically by 31ST December 2017, in FORM GST REG-29 at the common portal for the cancellation of registration granted to him. The Superintendent of Central Tax shall, after conducting such enquiry as deemed fit, cancel the said registration.
ii.) The cancellation of registration under the State Goods and Services Tax Act or the Union Territory Goods and Services Tax Act, as the case may be, shall be deemed to be a cancellation of registration under Central Goods and Services Tax Act.
iii.) In the event, the Superintendent of Central Tax has reasons to believe that the registration of a person is liable to be cancelled, a notice to such person in FORM GST REG-17, requiring him to show cause, within a period of seven working days from the date of the service of such notice, as to why his registration shall not be cancelled; will be issued.
iv.) The reply to the show cause notice issued has to be furnished by the registered person in FORM REG18 within a period of seven working days.
v.) In case the reply to the show cause notice is found to be satisfactory, the Superintendent of Central Tax will drop the proceedings and pass an order in FORM GST REG –20.
vi.) However, when the person who has submitted an application for cancellation of his registration is no longer liable to be registered or his registration is liable to be cancelled, the Superintendent of Central Tax will issue an order in FORM GST REG-19, within a period of thirty days from the date of application or, as the case may be, the date of the reply to the show cause issued, cancel the registration, with effect from a date to be determined by him and notify the taxable person, directing him to pay arrears of any tax, interest or penalty.
vii.) The registered person whose registration is cancelled shall pay an amount, by way of debit in the electronic credit ledger or electronic cash ledger, equivalent to the credit of input tax in respect of inputs held in stock and inputs contained in semi-finished or finished goods held in stock or capital goods or plant and machinery on the day immediately preceding the date of such cancellation or the output tax payable on such goods, whichever is higher.
viii.) In case of capital goods or plant and machinery, the taxable person shall pay an amount equal to the input tax credit taken on the said capital goods or plant and machinery, reduced by such percentage points as may be prescribed or the tax on the transaction value of such capital goods or plant and machinery under section 15, whichever is higher.
ix.) The cancellation of registration shall not affect the liability of the person to pay tax and other dues for any period prior to the date of cancellation whether or not such tax and other dues are determined before or after the date of cancellation.
Source: CBIC Website