Sometimes conflicts can be easily resolved - for example, if no changes we made in one of the copies since the last time the 2 copies were aligned, then it's usually safe to add the changes to this u-form. (This is one of the primary purposes of shepherding - if I add information to my local copy of a u-form the changes are apparent to other users of the Information Commons.)
However, if changes have been made to both copies that are incompatible with one another, more detailed algorithms and more careful reasoning is often needed to produce a definitive copy of the u-form. Conflict Resolution is a topic of active research.
