If you've created a reply to address or external email address for your Yahoo email account (example: sales@mywebsite.com), then you probably want to change the 'sending name' also. The sender name or send name is the name that appears in all the Yahoo emails you send by default, appearing just before your email address in the from field. Deleting the 'Send Name' in the email account profile won't solve the issue. Follow the instruction below to customize yahoo send name.

Set Yahoo send name

1. Log into your Yahoo email account.
2. Click on the gear in the top right of the screen.
3. Click 'Mail Accounts'.
4. Click the email account you want to modify listed under the '+ Add' button.
5. Enter the sender name you want to appear for this particular email address by inputting it into the 'Sending name:' field.
6. Click the 'Save' button.