Hi Sushant,
1) backup the original (evaluation license) e.g by renaming the original file from:
c:\Program Files (x86)\Freescale\CWS12v5.2\license.dat
to
c:\Program Files (x86)\Freescale\CWS12v5.2\license_eval.dat
2) copy the permanent license you obtained (license.dat) into
c:\Program Files (x86)\Freescale\CWS12v5.2\license.dat
3) run CodeWarrior and check the permanent license has been accepted (CodeWarrior IDE V5.2: Does my license.dat work?)
Hope it helps.
Stan