I don’t think this concept really applies, and there’s two ways of looking at it.
First, it’s established that Diana doesn’t send a contract 47’s way unless she’s thoroughly looked it over and determined it’s the kind of thing both he and she would have no issues with. 47, as a result, just takes whatever contracts she sends him because he trusts her to not accept any mission that involves being especially heinous, regardless of how much the pay is.
Second, even during those periods where 47 is not working with either ICA or Diana, he still gets plenty of work, but since he accepts such contracts himself, he’s already looked them over carefully to know if it’s something he’s down with. Since he doesn’t really have any personal contact info during such periods, he must be the one going to his clients, offering his services. Since 47 is only active as a hitman outside of Ort-Meyer’s control during the age of the internet, the dark web and underground communication networks exist during these times. 47 is likely choosing to take up a contract before the offering client even knows that he’s aware of it, and he offers them his services.
Taking these things into account, I don’t think 47 is ever in a situation where rejecting a contract can even be an option until he’s already started on one and realizes part-way in that the client has misled him about the details in some way. And even there, 47 makes it a point of professional integrity to never not complete a contract once he takes it, unless it is something deeply personal like the situation with Grey (which he still ended up unintentionally completing anyway), so unless he found out he’s been hired to kill off an entire orphanage or something, I doubt 47 would ever be at a point where he would directly reject a contract in a way that would cause his reputation to suffer.