Yahoo Mail: How to change account display name


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Hello! I am not trying to change the name displayed in outgoing mail. I am trying to change the displayed name that appears at the top right, when I log into Yahoo Mail. Long ago, I had changed my Yahoo account name to just the first letter of my name (A). Now I am trying to create a new specific long password for Yahoo Mail and it will not allow me to because my new password contains an A. It's rather important for me to use the password that I have created. Is it really not possible to change the account name? If so then I find that to be silly at best since I was able to change it to just an A, a few years ago.