blank page in edit mode

Hi Tom,

I have been working on my pages in Wordpress today. I was trying to make some changes. Some of my pages when I click on edit, there is just a blank page. I'm not sure what I've done! Is there something I may have accidently clicked on? I have just installed WR PageBuilder. Also I have been trying to remove the side bar layout on a couple of pages. I click on draft to make the changes , click update and then it goes back to the original settings. What am I doing wrong?
Thanks,
Lowana.