Undoing a merge

I noticed that someone made complete chaos of one of my family lines. They merged John Roach but not his parents, which is good because they are obviously totally different people. One was born in the UK and one was born in the US. The dates are different. The mother is different. I have no idea why they did this or how to undo it. From googling, I have found that this has to be done by a curator, so can anbody here help me? If you take a look, you can easily see that this profile should never have been merged.