Ok, you'll need to use the DNS Manager to change your A record.
In order to use DNS Manager, the name servers will need to be updated.
To set the A record, please try these steps:
1. First, log into your Domain Manager by following the instruction of the "Domain Manager Login" section here:
2. Once you're logged in, click on the domain name you want to edit.
3. Under Nameservers, click on "Set Nameservers".
4. In the pop-up window, select "I have specific nameservers for my domains".
5. Replace any name servers listed with the following:
6. Click on OK to save, wait a few minutes for the settings to go through, and then refresh the page.
7. When the nameservers change, you'll see some information under DNS Manager, and a link that says "Launch" - click that link to edit your DNS records.
8. The A record of your domain should be listed as the first record on the list. In the Actions columns on the left, click on the pencil/notepad icon to edit the record (make sure you click on the icon for the same line that the A record is on).
9. Finally, use the information provided to your by your new host to fill out the "Host Name" and "Points To IP Address". The field labeled "TTL" should stay in the default "1 Hour" value. Click on OK to save the new record.
That's it - your new A record should go live after a short delay.