Copy Project and Mass Change

hi experts,

When I copy a project from another operative project with list of material (external), the plant (in the material component) tab is also copied over to the new project. Is there any way that I could change this plant assignment for each material - it is greyed out in my system.

Additional information:

1. All of these material are Non-Stock (so Plant is irrelevant)

2. Procurement type = third party procurement (PFS)

Thanks, Tony