There is no Sunday sabbath for Christians in the Old Testament sense; there is no Saturday sabbath either. We are not under the law. If churches want to have services on Tuesdays, or if people want to work on Sundays and take Thursdays off, there is nothing to forbid it. But the sabbath - at least in terms of the Old Covenant law - is no more.
That is my understanding also, that is why i do not agree with the changing of the sabaath to sunday, if I were to keep the sabaath it would be on saturday. thank you.