How to edit the requisition structure of a posted requisition ?

Summary

How to edit the requisition structure of a posted requisition ?

Content

Hello,

We would like to be able to edit the structure of posted requisitions - i.e to edit for example the
business unit , and location fields.
Those fields are not editable as i see, if the requisition is in status - 'Posted' - please see attached file.

how can we edit those requisitions structure ?

 

Thanks,
Revital.