Providing client information is important as it builds strong bonding between the Client and the Company. It also helps to pass the fraud check activity.
Here is a short tutorial on how to change information in Hostpair.
Go to client area and click on Manage Domains. (Pointing by Red arrow in the picture below)
Then Click on Manage Domain. (Pointing by Red arrow in the picture below)
From the Management Tools option, select Contact Information. (Pointing by Red arrow in the picture below)
Now page will appear with many blank boxes (as like the picture below), put necessary information on the blank boxes and click on Save Changes. Your information will be changed.
Hope this tutorial will help you to know how to change the WHOIS information.