PAN Card

For a dual copy of the pan card, visit the NSDL website. There's a drop down in the application type where you need to select REPRINT OF PAN CARD. Fill & submit the form. You'll then get a token number on your email address. From there, you can continue to fill your PAN form and submit whatever documents are required, scanned copies of the documents. You can also mention the pan no. you want to retain. Further, make the required payment. You'll get a draft of your application form that needs to be printed & sent to the NSDL e-gov along with two photographs.

I was asking... A person holds two PAN cards so how he can return one PAN card?

oh, I am sorry i misinterpreted. In that case, you can either fill an online application on the same site. or you can also manually submit the application to this effect to the assessing officer. Fill in the important details like the details of the pan you need to retain, name and contact details etc.