I answered "To have a friend" at first, but then I thought about it a bit. I certainly need "to be a friend" more often than not.
Quite frankly, I'm terrible at keeping friends, because I tend to have a great best friend and then move on to the next one. There's a lot of people I consider acquaintances, some that I even consider as strangers now. And that's mostly to do with me not really putting in the effort to keep the friendship going. I know that a huge percentage of these people still consider me as a friend, hell, a few still treat me the same way as if nothing changed, but I don't share the same feeling anymore. Part of me likes to believe that I do everything in my power to keep a friend, but I'm rational enough to know that's not the case. I often wish I could change that, but another part of me doesn't care enough to go back because it's so in the past.
..but I dunno, maybe I'm just a prick that doesn't know what to do with friends. Maybe I'm opening myself up more than I need to, but I thought I'd give my two cents on this~