option 1 is better . 

2) if you are shifting to kolkata change registered office of company to kolkata and do GST registration in kolkta 

After the registered office of a company is declared by Filing the INC 22. In case there are any changes in the registered office of the company it must be intimated to the ROC. If the change in the registered office address is within the same area of city or town or village it must be notified within 15 days by filing the relevant forms.

If the change of the registered office address is outside the limits of the city or town or village then the registered office must approve a special resolution passed by the company. Suppose the registered office of the company is to be changed from one jurisdiction of a ROC to another jurisdiction, then the change should be approved by the Regional Director of the ROC.

MCA has provided procedures to change the address of the company, this must be followed by the company.

Types of changes in the address of the registered office.

• Within the same city
• Within the same state and ROC
• To other ROC in the same state
• From one state to another

The MOA of the company changes as the registered office address also changes.

• It is necessary to hold a board meeting and pass a resolution to call an extraordinary general meeting.
• A special resolution is to be passed in the EGM about the change in the address of the registered office as well as for altering the MOA. The resolution must be filed in MGT14 within 30 days with the MCA.
• The company has to publish an advertisement for shifting the office not more than 30 days before the date of application to the regional director. It should be published in at least vernacular or the regional newspaper and in an English newspaper.
• The company should also send a notice to the creditors and the debenture holders if there are any and to other regulatory bodies as applicable to the company.
• An application to the Regional Director should be filed for shifting the registered office along with the documents that are specified.
• In case an objection is received then there is a hearing with the Central government and necessary orders will be passed. If no objection is received, then the order will be passed without any hearing.
• The confirmation received from the RD to the ROCs is to be filed by the company within 30 days from the date of the order.
• Within 30 days it is necessary to file form INC-22 to the ROC with the required documents.

The central government should dispose of the change of the registered office application outside the state within 60 days of the application and before passing the resolution it should confirm that the change is with the consent of the creditors, debenture holder, etc. The approval by the central government shall be filed with the registrars of both states. The ROC of the state wherein the new office will be located has to register the same and a new certificate of incorporation should be issued.

Dear Client, 

The former option is the most appropriate and valid one as per the Companies Act and it will avoid more legal problems in the future compared to the second one. 

Thank you.

Yes it's a convenient one as aforesaid

Change both the registered address and GST registration to Kolkata

if you keep the registered address at Bangalore then all compliance under the companies act will have to be done with the registrar of companies at bangalore which will create logistical issues for you

also if any suit is filed against the company and its registered address is at Bangalore then such suit will be filed before the competent court in Bangalore and not in Kolkata which will again raise logistical issues and cause you inconvenience