Performing a Three-way Compare
A three-way compare is used to compare your changes to a Process Package with those of another user, as well as with the original (common ancestor) file on which both are based.
Typically, you might want to do this if another user checked a process package out of Subversion when you did, and they made changes and checked them back in. When you go to check your own version back in, Subversion identifies a potential conflict. To identify areas which the other user has changed and decide whether to adopt their changes and abandon yours, or overwrite them with your own, you can do a three-way compare.
See Source Control for information about using source control to control your project information.
To do a three-way compare (when you have checked a project file out of the source repository and made changes and saved them - and another user has done the same and commited their changes):