How can I stop particular user to edit a requisition from the notification summary?

I need to stop some user to edit the requsition from the notification summary.

Approver can modify is at the level of the document type and not at the user level

I did a personalization for the notification summary but "edit document" and "view document" and "open document" all of them are hidden now, not 'edit document alone

also there is the worklist when I login where I can edit the requsition , this worloist is at the operating uinit level

How can I stop particular user to edit a requisition from the notification summary?