The best thing to do in such a situation, it's just an honest conversation with a friend. Maybe you did something bad, but they have not noticed, and the conversation will help figure it out. And she may be just now so many things to do that don't have time for anything else. Take the initiative to communicate, even if your meetings are not as frequent as before, but interesting and memorable.
If the cause of broken relationships has become your fight, take the first step towards reconciliation, especially if you were wrong. Many people are afraid to put up first because they believe that thereby they show their weakness, spinelessness, etc. But think what is more important: your pride or your girlfriend?
If you decide on a Frank conversation, then swipe it into a soft, gentle form. Tell us about how you lack of communication with a friendwhat you are going through because of disagreements that I would like to return relations to normal. But in any case, do not stoop to rudeness, don't blame the friend, even if it is her fault, don't bring up old grudges. This you only make it worse. All claims need to make correct and good-naturedly.
If you see that a friend doesn't make contact, don't push her, give her time to cool down and rethink the situation. After some time try to establish a relationship, and maybe she'll try to do it, only in this case, not to alienate her, arguing that it was necessary to put up before.
Seek help from your mutual friends. They most likely too embarrassed that you don't communicate with her best friend, as it is reflected in mutualrelationsthe company as a whole. Maybe in this situation your friend will be easier to listen to the opinions of other people than to your because of you she's hurt.
Think, and whether it is necessary to restore the relationship with a friend? Before you had a lot of common interests, topics of conversation, but eventually all the people in varying degrees, are changing. Maybe you have not noticed, how became from a friend absolutely strangers to each other people? Family, life, work have changed your interests and Hobbies. Then how would you not tried to regain the relationship you, unfortunately, will not succeed. You can only try to keep the relationship on a friendly level, but to expect anything more is not worth it.