I have a few ideas for you, let me know if any of them will help get you closer to your goal.
First, you can set a page to have "No Layout"
Head to Website->My Webpages and select the webpage you would like to edit
Head to the Settings tab
Under the "Page Layout" option you can select "No Layout"
If this is not enough, you can also edit the headers themselves.
Head to Settings->Administrator
In the box titled Theme Editor click on "Header"
Now you can edit the header as needed, just remember to hit the save button in the top left of the editor!
If you notice, in the Theme Editor box under Settings->Administrator there is a "Header" and also a "No Layout Header." So if you need some pages to show the header, and others to not, you can edit the "No Layout Header" to appear as you would like. Then make sure the pages that need the edited header are set to "No Layout." Otherwise, if every page is going to look the same, I would recommend just editing "Header" and letting that affect all pages.
Please let me know if this helps or if you have more questions!
