Thanks a lot for your reply.
Couple of doubts:-
If composer finds one to one realtionship between the symbol pins and the pins in schematic, then I think one can exploit this relationship. What I mean is:- Suppose there is a PIN A in schematic and corresponding one in Symbol. If I rename PIN A to B,then through the above relationship the corresponding PIN in symbol should change to B. Of course adding a NEW pin is totally a different story.
I think if I have modified the original created symbol by composer ( it is generally a square/rectangle) to a suitable circuit looking symbol let's say for example a OPAMP symbol for a OPAMP circuit, then Create -> CellView-.... method will change the shape from OPAMP to a rectangle which I don't want.