Is it possible to reset someone's Hotmail password and then change it back to the original?

I'm trying to gain access to this person's account, and I can do that by resetting their password, but I think they might notice if their old password suddenly doesn't work anymore. Is there a way I can change it temporarily, then change it back to the old password without knowing what the old password is?|||No. I won't question your decision of violating another person's privacy, because I don't know the circumstances, but there is no way of doing this.