If you work in a multiple-stream UCM project, you rebase your work area to stay up-to-date with other developers' work.
After you prepare your development view, you can start the rebase operation (more information is available on preparing your development view).
By default, in a multiple-stream project, you rebase your development stream either to baselines recommended by the parent stream or to baselines created by the parent. Typically, these recommended baselines are created by other streams in the project.
In a single-stream project, an integrator rebases the integration stream to identify a major project milestone (more information is available on rebasing in a single-stream project).