I created a composition & I used that comp in my project here and there (more than 30 places).
When I have Post-Rendered it, It replaced the comp with the Rendered video.
At that time it was perfect.
Now I wanna edit the comp. If I edit that comp, Do I have to change the rendered video with my Edited-comp everywhere?
Is there any way where I can,
First - Replace the Post-rendered video with my comp (Not edited).
Second - Edit that comp.
You can use the Replace Footage command. Highlight the layer you want to replace. Go to the project pane and highlight the clip -- in your case, a comp -- to replace the layer. Alt-drag (Opt-drag Mac) the clip onto the layer. If you have more than one layer in the comp to be replaced by the same clip, you can do them all at once.
Now -- if you did NOT stipulate that you wanted to replace a pre rendered clip with a comp, this would be a lot easier. You would pre render the comp. If the new comp has the same name as the old one, the new prerender would just replace the old one.
You can replace items on the timeline by selecting the layer and Alt-dragging the new item onto it. you have to do it individually for all comps, though. There is no way to replace a fooatge item with a comp in the project window directly.