http://www.bioinformatics.org/pdbeditor/wiki/

You can easily done it manually, by removing the htatm and undesired chains from the text file of .pdb ...

if you have linux

cat 3K7Z.pdb |grep -v HETATM > 3K7Z_2.pdb

where 3K7Z is the file and HETATM is the sentence you would like to like to search in the line do decide if needs to be removed.

> tells where to save the file

to check for more options

man grep

you can also use regex what will give you a lot more of ways to decide what line to remove or not.

Thank you Michal and all. It worked with SissPDB viewer

http://www.bioinformatics.org/pdbeditor/wiki/