Soory for the inconvenience.
I have followed the following steps:
Tasks-> Shrink -> Files
Select a data file(.NDF) of Primary file group.
Select radio button for :
Reorganize pages before relaesing unused space
Shrink file to
I have provided shrink upto 1 GB more than the actual data size.
Still the size of the datafile continues to be the same.
Please let me know if you need any other details.