Leadership is a full-contact sport, and if you cannot or will not address conflict in a healthy, productive fashion, you should not be in a leadership role.

FORBES: 5 Keys of Dealing with Workplace Conflict

If the conversation doesn't yield desired results, the infraction is too severe to not be reported to someone in authority or you simply cannot handle a direct confrontation, you may need to contact others.

CNN: Difference between tattling, reporting a concern at work