Per https://developer.apple.com/library/ios/documentation/LanguagesUtilities/Conceptual/iTunesConnect_Guide/Appendices/Properties.html, the Bundle ID "can’t be edited after the app is approved."
So, if you have app has previously been approved, then you can't change your Bundle ID. But, if your app has NEVER been approved, then you should be able to change your Bundle ID.
I think your issue is that your app is currently in the App Store review process. I would click on "Binary Details" and then click "Reject this Binary" at the top right. This will remove your app from the App Store review process (status will be "Developer Rejected")and you should now be able to edit your Bundle ID and then resubmit for review.
However, I am assuming your app has never been previously approved. If it has been approved before, I think you need to create an entirely new app.
Hope this helps!