In your personal account select item "Domains", "Active Services" menu.
In the appeared table click on the domain to be unlocked.
Click "Modify" on the domain page in your personal account in "Whois contacts" line of "Account" table. On "Data update" page click on "Edit". Specify the new, earlier confirmed e-mail address and click on "Save changes".
Ensure that the new e-mail was earlier validated – domain will no longer have E-mail not validated" status.