This is a question we get asked occasionally, so I'll show you here how to do it.
Your site doesn't need to be setup to be multilanguage to use this feature, it'll work on single language sites too.
First things first you need to go to the Administrator area of Jomres and click on the Label Translations menu option
Next search the page using the web browser's seach feature for the gateway name you want to change.
Click on the item you want to rename, a popup will show where you can enter new text. Put in the new name for the gateway, then click the Check button. That'll save the change.
Now when you go to the property configuration page you'll see that the gateway has been renamed