The single control account workflows (for example, BCR, FCR) do not support adding the control account in Open Plan. For these items, the control account must be selected in the item form before starting the workflow.
The multiple control account workflows (for example, CCR) support adding additional control accounts in Open Plan; however, a change request can only span a single Open Plan project. If there are many Open Plan projects to one PM Compass project, all selected control accounts as well as all activities that feed those control accounts must be contained within the same Open Plan project.