How to Send Notification exactly 10 days before Due Date in ServiceNow?

Open table list view and add below filter:

Create Scheduled Job and run daily:

var gr=new GlideRecord("sc_req_item");
gr.addEncodedQuery("due_dateRELATIVELT@dayofweek@ago@9^due_dateRELATIVEGT@dayofweek@ago@11");
gr.query();
if(gr.next())
{
gs.eventQueue("notify.user.reminder",gr,gs.getUser(),gs.getUserID());
}