It is definitely crucial to pinpoint that “how” if you are meaning to revive the friendship. This should be the first step on your journey to revival because without knowing where you went wrong in the first place you can't expect to rebuild a lasting friendship. Most times, the friendship usually just fades away because efforts from both sides stop intentionally or unintentionally. We fail to realise that friendships also require active effort to flourish. But, if the reason for you guys not remaining good friends is anything related to betrayal or some other form of hurt, it's better to rethink carefully before venturing out again.
Once you have identified where it all went wrong, it's time to reach out and communicate. How to reach out will vary depending on the distance that has been created between you. Sometimes, just calling them up and talking like old times will do the trick. But you need to keep that up. Maybe the friendship faded because you don't get to see each other as much anymore; to fix that try and make some time for each other. If too much distance has already been created, it is also important to understand how that person you're trying to reach out to might not even be the same person anymore. You might have known the name of all their school crushes and every grade they received all throughout school, but you should be prepared to get to know them all over again. Also, it is important to understand that you might not even like this new person they have become.
Lastly, before you reach out, you need to ask yourself whether the only reason you two were close friends in the first place was because you were forced to see each other on a regular basis and once life got in the way, none of you cared enough to stay in contact. The foundation that you based your friendship on is also important as the two of you might have reached a point where you find it difficult to relate to each other. In such cases, you need to remember that sometimes it is okay to outgrow friendships. So, before you go out there you need to be sure whether this friendship is even worth rekindling.
Tasnim Odrika likes pineapple on pizza and is willing to fight anyone who opposes her on this. Reach her at firstname.lastname@example.org