Use
Changes to existing planned orders can be necessary, for example, if the planned order in question is firmed, but then receives a rescheduling proposal during the planning run.
Procedure
The initial screen for changing a planned order now appears.
The detail screen for changing a planned order now appears.

If you change a planned order, it is then regarded as firmed for the planning run, (as is a planned order that is created manually). Thus, it will not be changed automatically during subsequent planning runs.