How to move a diagram between projects?

I'm a very basic user of EA. I never had the time to learn its terminology or features and therefore i only use it to create pretty basic (yet rather big) diagrams.

Unfortunately my EA project file was updated by another person and now i need to move a diagram from the old version to the new one. I thought this could be a simple copy-paste action but it doesn't seem to be possible.

Any idea how to move the diagram to the new project file? (keep in mind i don't really care about keeping elements or whatever)

Solution

The best way is likely the following (assuming that all elements are still present and only the diagram has been changed and the other project is something like a previous backup version):

Enter the old project
Create a dummy package
Move the diagram in question into that package
Export the package as XMI
Enter the recent repository
Import the package from the XMI
Voila, there is your diagram. You can replace the old one or keep both as you wish
Remove the dummy package as you will no longer need it