First, maintain your composure, anger does not bring about any solution;
The first step is to talk about it as soon as possiblePrepare what you will say to your colleague beforehand. State facts and avoid gossip and personal attacks.
Identify the causes and explain the problem in the first-person, with the use of "I";
Listen attentively to your colleague's point of view without interruption;
Find out what you agree and disagree upon;
Look for solutions by clearly explaining what you want in a positive way;
Choose a solution and remember to remain open to a compromise.
If the problem persists, do not hesitate to speak with your immediate supervisor to help resolve the conflict.