Step 1 : Go to https://www.123-reg.co.uk
Step 2 : Fill Email and Password Then click “sign In” Button.
Step 3 : After Successfully Sing In you will get below window and click DNS button under domain section.
Step 4: Then Go Nameservers tab in navigation bar.
Step 5 : After click “Change Nameservers” button.
Step 6 : After that you will get below window and tick “I’ll use my own nameservers” Line and Give Your Prefer name to your server in fields and click save button.
Step 7 : Finally You change your server name successfully and click continue button.