First of all, you should face the person who is bothering you, otherwise the situation will remain there and you will not be able to resolve it in any way.
You should talk to the person face to face. Make sure you stay calm and patient during the conversation. Discuss all aspects that are creating problem between both of you.
The conversation should be in a friendly manner and hostility should be avoided in any case whatsoever. A friendly conversation will help in eliminating or at least reducing the conflict right away.
You should give importance to everything that other person says to you and try your best to understand his or her point. Evaluate whether he or she is wrong or right and then prolong the conversation accordingly.
Make your point clear to your colleague in a decent tone and express all of your concerns. Do not become aggressive at any point during the conversation.
Make sure you show flexibility in your behaviour while talking to your colleague and also try to convince him or her while staying calm.
If you fail to resolve the conflict by yourself, then you need to involve the supervisor or manager who will resolve the problem according to the rules and regulations of the workplace.