In an article for Fast Company, James Richman shares some pointers for disagreeing with the boss in the most casual and forthright way possible. At its heart, all such interactions depend upon there being trust between you and your boss. This must exist for meaningful dialogue to occur. That being said, Richman says to “let the small stuff slide.” Nobody enjoys being at odds with each other all the time, so pick your battles. Likewise, pick the right time at which to bring up your disagreement, when your boss is not too busy or stressed, and make it clear that your contention is nothing personal against your boss. Try to anticipate in advance problems that your boss might have with your alternative and address them as you present the idea.
You can view the full article here: http://www.fastcompany.com/3050475/know-it-all/how-to-disagree-with-your-boss-constructively