Don't let anyone question or suggest a certain way to be or behave a certain way whom questions your beliefs and whatever magick or religion you are involved in.
Magick is a science, not a do-whatever-you-want form of artistic self-expression. There are things that simply do not work or which cannot be done or which can only be accomplished in specific ways. If you could accomplish literally anything through magick, in absolutely any way you wanted, the world would have thousands of lotto winners, teenage werewolves and mermaids, and the singers of One Direction would have more true loves than they could possibly count.
Yes, let people question your beliefs and magical behaviors and convictions. Encourage people to question them. Question them yourself! Ask lots and lots of questions so that you can find out which things are real and true so you can discard the rest.
On the subject of your friend wanting to have a different work shift, I'd suggest a prayer or spell which deals in making their target audience (presumably their superior at work) be more receptive to what they say, but they still need to ask for them for a change in shift. If the absolutely cannot or will not ask then I'd suggest petitioning a deity or a more minor spirit to go nudge the boss and circumstances until they change your friend's shift of their own accord, but that's not the route I'd take so I'm not real sure who to petition for that - my guess would be something Mercurial.