The unfailingly polite Siri will, by default, address you with whatever first name you entered on your contact card.
But in addition to being polite, Siri is also obedient—and that means she’ll call you anything you want. All you have to do is ask.
Just press and hold the Home key to launch Siri, then say something like:
From now on, call me ‘Scooter.’
When you do, Siri will add the nickname “Scooter” to your contact card—and from now on, Siri will call you “Scooter” (or whatever name you like) whenever the occasion arises.
Having second thoughts about your new nickname? You can always ask Siri to go back to calling you by your real name, if you wish.
You can also tell Siri your relationship to any of your contacts—meaning, for example, that you can tell her “Michael Scott is my boss.”
Once that’s done, you can say “Call my boss” to Siri, and she’ll start dialing the right person.