Normally, whenever you want to create any entry in sage X3, there are two ways,
1. either by clicking the "New Button"
2. "Modifying the existing entry", just need to remove the entry number, press TAB, and all of the attributes of the existing entry will be copied for new entries. after a few modifications, you can create a new entry.

I want to disable this "Modification function" on "Sales Order" that should be applicable for certain users.
this function is already applicable to "Purchase Invoice".