There's a good chance that it would be cheaper to buy a ticket to fly back to EWR from DFW if you want to visit the NYC/NJ area. In fact, if you call after landing and clearing immigration and customs, chances are that the phone agent won't be able to tell you the amount of any refund, if applicable, although they should be able to tell you how much more it will cost to change the ticket.

BTW, are you aware of the rule starting May 4th about many people from India not being permitted to enter the USA due to COVID-19, even with a negative test.