Thanks Neil , for your reply
Actually I am using Thermocouple for temperature measurement and as you mentioned that noise may get induced due to long driving cables is really a concern . but I am using twisted pair cable so , even if any EMI /Noise gets induced it would be equal in both cables and should get cancelled out mutually , leaving my very small differential process signal unaffected that i can get measured using single OP-AMP in single ended configuration.( For eg: Non-Inverting Amplifier )
Then why should I use Instrumentation Amplifier , as the noise would be getting cancelled in the twisted pair itself .