As per Income Tax Law, holding more than one PAN card is a criminal offense as per the Act.

A person cannot hold more than one PAN Card and we do not know the circumstances that may have led to a duplicate card. A penalty of Rs 10,000/- is liable to be imposed under section 272B of the Income-tax Act, 1961 for having more than one PAN.

Click here to download Automated Excel Based New Pan Card Application Form 49A

How to Cancel or Surrender PAN Card Online?

1.      Visit Income Tax Sparsh Site
2.     Provide your basic information such as Contact Number, Name, Last Name, DOB and father's name.
3.     Other details regarding additional Permanent Account Numbers that are to be surrendered.
4.     Note that one needs to be aware of all the PAN card numbers and details regarding the card.
5.     And one needs to mention the PAN card which needs to be retained.
Alternatively, you may fill and submit PAN Change Request application form by mentioning the PAN which you are using currently on top of the form. All other PAN/s inadvertently allotted to you should be mentioned at item no. 11 of the form and the corresponding PAN card copy/s should be submitted for cancellation along with the form.

Manual Method To Surrender The PAN Card

If an assessee wishes to cancel/ surrender your PAN (which you are currently using), then you need to visit your local Income Tax Assessing Officer with a request letter to cancel or surrender your PAN. 
In the application you need to specify your name, contact details, PAN card details to be retained and details of the PAN card that has to be surrendered.
Maintain the receipt or acknowledgment of the application should be retained as that serves as the proof of surrender of duplicate PAN.
Make sure you have surrendered the duplicate copy of pan cards to avoid penalty from the tax department.

Why It's Important To Surrender Your Pan Card?

As mentioned earlier it is a criminal offense to hold more then two PAN Cards. It's best to have them surrendered. In case a lady has married she need not apply for another PAN Card because of change of surname. She can simply get her name changed on the PAN Card. 

Applying for another PAN Card after marriage would once again lead to duplicate cards which is not permitted. The procedure in this case is also not tedious and you can get in changed easily.