We, personally, not recommend you to change nickname through this ways.The second, you can change by using change nickname software.
Remember even though you have new nickname, the nickname of yours in your friend messenger list still remain the old nickname, unless they change it into new one.
New Ways to Change Yahoo Messenger Nickname Just login to your Yahoo Account (use login username of your desired alias ID or primary ID of Yahoo) then.
Just visit: Yahoo Profile You will see a Page like this: After that, click the Continue Button at the right of the page, and you will see a page like this: Now finish your edit Profiles.
Note: Yahoo closed down the ways we can change our nickname, if you have a nickname that been edited or changed in the past before yahoo has closed down the edit profile and nickname, you still able to use it in chat room: ASCII or Invisible Nickname] Nickname almost like a call’s name. Your friend can change the nickname of yours whatever and whenever they want to.
Remember in Messenger List of your friends, your nickname not in your controls.
In Instant Messenger, in Messenger List, nickname represent the name of yours! In chat room (if you using official chat client of YM), your nickname will appear in the talk chat room, only by clicking your nickname or hovering the mouse on the nickname your real identities (username or ID) can be seen by others.To change nickname of yours, You can make simple steps that we given to you below.Note: this only will change the nickname appear in chat room not in Messenger List of your friends.There are three ways to change the nickname of your IDs.First through chat room yahoo messenger ( only available in Yahoo Messenger version 8): Unfortunately, this ways of changing nickname sometime did not support ASCII character.