Wrong email address

Hello,
Outbid notifications and "register your account" emails are sent from auction@mywebsite.com. However, emails according password changes are sent from webmaster@mywebsite.com. How can I change this to auction@mywebsite.com?
Thanks in advance.
Outbid notifications and "register your account" emails are sent from auction@mywebsite.com. However, emails according password changes are sent from webmaster@mywebsite.com. How can I change this to auction@mywebsite.com?
Thanks in advance.