The Push Back Process — Step 1: Get out the anger in a safe environment or the right person! (Never a coworker!) Step 2: Write what you want to say in your most down-and-dirty, no editing way. Step 3: Rewrite your comments by putting as much as possible in the third-person, objective case. Cut out every “I” and “me” possible. Depersonalize their intent or behavior (no matter how nuts it may have been). Step 4: Offer an alternative to them that is reasonable and better for you.
Source: Unreasonable requests: how do you push back? | The Corporate Writer