How to change te flat rate name on check out

I just bought this extension: http://www.opencart.com/index.php?route ... lat%20rate

However on the check out page it states the name of the extension and not the name I gave it when using the check out. I want to delete this part.

You should contact the author of the extension for support. It's unlikely anyone here is going to be able to assist you with a commercial extension.

If they're unwilling or unable to help, and you want a multi flat rate shipping method that works (and has easily editable Titles for rates), I have a Multi Flat Rate Shipping extension.