Under normal circumstances, project managers use baselines (which reside on a project integration stream or on the parent stream of a development stream) to share work between projects. However, if you start work on an activity in your development stream and then determine that you cannot complete the work for the current project, move the work to the project in which you intend to complete it.
To facilitate the merge process, move the work to the new project as soon as you determine that you cannot complete it in the original project. (The longer you wait to merge the work, the less you may remember about it and the greater the potential for merge conflicts.)
Do not work in a development stream that contains activities that you do not intend to complete for the current project; doing so may prevent the rebase operation from synchronizing your development stream with the work in the baseline.