I think he means if his friends name is butramar84694992sss2294949192kdj21 how can he change it to bob
I'm not sure if you can do that with AIM but I use a program that I recommend called Trillian. Trillian will allow you to change peoples' screen names on your computer so when SuperSniper1082 messages you, you can change their display name to something like Jason or whatever you want. Trillian runs AIM, MSN, IRC, IRQ, and Yahoo so you can be logged on to all of those things at once or just AIM if that is all you use. it has a ton of cool features like conversation logging and easy copying to clipboard just by highlighting. try it http://www.ceruleanstudios.com/
I'm pretty sure you can do it by right-clicking on the user's name. If that doesn't work, try looking through the buddy list options.
I dont really like trillian becuase i dont use all of them...I only need aim and skype and it doesnt have skype so...
If you want to change SNs then you have to D/L the extension of AIM called MiddleMan you need a version of AIM on your computer don't get the latest ones like 5.9....something like that.
if you have the newest version of aim right click their name on the buddy list, click edit buddy then at the top of the box type their name where it says nick name. then click view at the top of the buddy list then friendly names. hope that helped =] ~v3kt0r