I am in the process of asking for a salary adjustment. I am trying to state in a letter that I am able to accomplish certain major tasks without being able to fall back on anyone for help. Basically, I have a certain skill that I can't rely on any coworkers for because they don't posses this skill and there's no one else in my role. How can I properly phrase this without being offensive to my boss, who doesn't have this skill?
I'm trying to demonstrate value by including this and am looking for a single sentence.