use load step solver

apply all load and save it using LSWRITE,1

then change the load corresponding to your case and write second load step using LSWRITE,2,

finally you can solve it LSSOLVE,1,2,1

Dear Varadaraju Magesh, Added to the answer of Tomasz, I would suggest you to use a ramped load step with a realistic ramping time. You might refer to the following page: http://www.ansys.stuba.sk/html/guide_55/g-bas/GBAS2.htm. Best of Luck.

Thank you very much sir. I will try.

In addition the above answers, I suggest you to apply the load as a displacement and you can start from high value and decrease it gradually.