I edited few files in my workspace and did p4 change. Then I remembered that I have to make some more edits to additional files(not in the changelist). I opened those files with p4 edit but how to add these files to existing changelist. Is there a way to do it?
In general you can use:
p4 reopen -c CLN FILE ...
to move open files into the specified changelist (regardless of whether they were open for edit, add, etc.).
CLN may be default to dissociate the specified files from any numbered changelist.