Domain administration password is password used when registering domain name. It's important to remember
for it's used to access any of domain name services (e.g. change WHOIS information, change DNS records).
After you log-in on the left side menu bar under the tab "Domain name operations" you will find a link
"Modify domain password". From the drop down list choose the domain name that you want to modify. You'll be
prompted to insert old (current) domain name administrative password and the new one. After
successful change you'll be informed that everything went in correct order and that servers has accepted
new domain name administration password.
If you would like to change registrant's name you cannot do it using "Modify domain info" option in "Domain operations" section.
This is possible if you click on option "Change domain ownership" of "Domain & name transfers" section where you will be able
to change ONLY registrant's name.