Changing the contacts of a single domain
If you only have one domain, or if you only need to change the contact(s) of one domain, you can do so directly from the domain's control panel, by clicking on the “Modify” link that is under the contact information.
This will bring up a form that will let you change the Gandi handle for the one that you chose to modify.
Simply specify the handle that you want and click on “Submit” to apply the change. You will then be taken to a confirmation screen, where you can return to your domain's control panel.