You can change the name that appears on your profile by going to the "My Profile" tab and clicking on the "Edit this Section" link, next to "Basic" on you Profile page. On the page that appears, change your name as desired, and make sure that you click on 'Save Profile' when you're done. The name that appears on your profile page will be the same as the First Name that you enter here."
... if you want to change the URL that points to your page, you may not like what hi5.com has to say about it:
"You can create your own hi5 URL by going to the "Edit Profile" link beside your account photo on your home page. Select the "Basic" tab. Enter the nickname you wish to have in your URL and click "Save". Once you select your hi5 URL, you won't be able to change or delete it."
I know some site let you merge two accounts, unfortunately hi5.com doesn't:
"Merge 2 hi5 accounts
Currently, we do not have the option of merging two hi5 accounts. The feature of transferring your friends from one hi5 account to another is also not available on hi5. Please send out friend requests to all the friends who are not in your preferred account. Once they have all accepted, you can delete the other account."
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