Change fees can vary wildly depending on country of origin.

The fee for India-originating itineraries is usually a very reasonably INR 2000 (about USD 40), but the corresponding fee from the USA for a reciprocal itinerary can be as much as USD 200. For the most part however USD 50 to USD 150 equivalent seems to be the norm.

It's also been my experience that Emirates "forgets" to charge the change fee about half the time.