At my pediatrician office i can just tell her if i want him to get the vaccination or not i did agree to let him have all of them when he's supposed to get them. But if i was to not want that i could just say no@moonslugg every office is different though.
Usually a form saying you have been given adequate information on what vaccines they're getting and you understand it. If you choose to withhold any of the vaccines for any reason, you also sign a form saying you did and why. ( I didn't like mine getting more than two shots at once, so I always spaced it.)