Does a person invalidate an act of worship merely by intending to invalidate it before commencing it?

What a person intends before an act of worship does not affect its validity. The validity of worship depends on the intention occurring at its designated time and not being revoked during the act itself. Therefore, if the intention exists before the worship and is not interrupted during it, the worship is valid. What one previously intended, such as interrupting the worship after starting it, does not affect its validity, because that intention was not acted upon.