I have multiple compositions and after I was done, I went back to make a change in one compositions layer but it didn't take effect in my final composition? How do you make it recognize the change?
Not sure what you mean. Unless they are somehow nested, different compositions have no relation to one another. Just changing a layer in comp A will not affect comp B. Anyway, this is not going anywhere. Provide screenshots of the timelines and project structure, if you need more specific advise.
If your changed composition is nested in the final then the change will show up. If it is not, it won't. It's that simple.
Look at this flow chart of a fairly substantial animation I'm working on this morning. 200+layers. In the center column you can see Group 2, Group 3, and Group 4. These are all nested comps that use the same source footage. If I change any of the animations in either of these nested compositions, then the change will show up in the General V1 Composition. If I change any of the footage by editing it in an external app, it will change every instance of the footage in every comp. For Example, the top footage item (woman/ns....) in the right column is used in all 3 nested comp's but, if you look closely, the footage is also repeated in the general comp.
I hope this helps.