Migrating unfinished work to a follow-on project
Work is in progress in project PA, but must be delivered before work in stream DA can be completed. Follow-on work continues in project PB which starts from recommended baselines PA.BL2 in the integration stream of project PA. (The integration streams in projects PA and PB are siblings because they share a parent, project PA.)
You can migrate the changes in activity a1 to a cousin stream DB in project PB by using an alternate target deliver operation. Only the changes in activity a1 are delivered because the remaining contents of stream DA are in stream DB. Work on the feature that started in stream DA can be continued in stream DB.