You'd have to reticket before boarding to ensure that you get the full miles. This could mean paying any change fees involved with your original ticket and upgrading to the return business fare which is 99590 Indian Rupees. You might be able to just upgrade one-way if your fare is combinable with business fares. Just call EK and find out what the new fare would be. You may not be able to get anything cheaper than the return business fare. Depending on your dates of travel, you could also see what two separate one way tickets would cost--one in business and one in coach.

If you pay a co-pay to get yourself upgraded at the airport or on board and your ticket is not reissued, you will only get credit for coach travel.