Hello everyone! Hope you are doing well! I have a doubt which requires your assistance. I have to visit the US for some observerships. I have booked a roundtrip from Kolkata to New York and I am flying Airindia. Though the departure dates are fixed, the return dates still aren't. We depart on April 30th and the return booking is in July 3rd, 2017. However, circumstances might change, so we might need to delay our return till 4th August 2017. We will only know of our final plans once we arrive in the US, sometime late in May. Can we change our return flight at that point of time? How do we go about it? What might be the charges and regulations? We are flying Economy and we had booked online. Since the booking was made from India on an Indian credit card, are we going to pay with INR or USD at the time of the change? Do we still need to use the same card as well? Thank you for going through and for your valuable suggestions!