When I texted Steven Gibbs (seems like a huge dbag) asking if the HDR could be used to alter the past, he said yes.. I'm guessing he was lying outright.
Well, I remember Steven Gibbs said in some sort of document about the HDR that takes you to a timeline that's 2 or 3% different, so you may be able to alter another timeline's past, but not this current one.
Do you return to your current one?