Re-validating PIO vs travelling with both passports

[nsg_lists]

I am sorry if this is the wrong forum, but I could not find a better forum to post this question.

 

I have a PIO card for my child. A few years back, she got her US passport renewed. Now I know that I have 2 options,
(1) Revalidate PIO card with new passport information.
(2) Travel with both the passports and the existing PIO.

The first option is easy enough. For the second option, I am trying to find proof that I can travel using the old PIO card as long as I have both the new and old US passports on the Indian Government site. Could someone advise where to find the information on an official site. I want to take a printout of it when traveling in case I encounter any issues. I plan to travel later this year in 2014.