I have a slew of lower thirds that I create. And I am very Proud! But, the powers to be have made a change. I had to create a solid for one of the comps. How to I copy and paste that solid into the other comps. I have to open each one individually since it is saved as its own file.
I don't know the nuances of AE, and am round tripping each lower third into premier pro to update it.
G5, 1.7, 4MB RAM, 30"cine, G4, 1.6 2MB RAM, Mbox, Neumann TLM-103, FCP HD 5. Pro Tools, Adobe Creative Suite, Reason 3.0, Macromedia Studio, ProAnimator, HVX200 with Firestore v4.0
You didn't really give enough info about the setup of your project or the kind of change you need to make so I'm not sure I understand your question, but I'll mention a couple things that should help ...
If you've saved all your lower thirds as individual AE project files, you can import them all into one master AE project.
If a number of your lower thirds are the same elements and animations only with different names, you can make changes to the solid and check the box that says "affect all layers that use this solid", rather than copying and pasting the solid into each one. However, that won't work if the change to the solid is an effect or animation applied to it. In that case, you'd need to make the change in one of the comps and copy it into the others.
I think you will have learned this from what you're facing now, but I'd suggest always building your AE projects in ways that will make any type of changes as quick and easy as possible.