There is a strange bug in Facebook that has effected some Facebok pages. Because of this user are unable to update Facebook page info. When user click on edit page info, or update info they get blank page thus unable to edit page info.
This bug existed since months and some pages are only effected. Out of 4 pages I own 1 of them is effected. I tried asking in Facebook Help Center but it yield no return. So, I began experimenting thing and finally found temporary solution.
First of all download “Facebook Page Manager” in your smartphone. I used Android Nexus 7 but this should work in other iOS and Android device as well.
After that launch the application, select the page you want to edit and click “Edit Page” (shown in picture below). This will let you do basic editing of short description and url. If this is what you wanted to edit this will help. If you have found any other fix let us know.