It's a difficult one. Me and my OH has chosen our baby names quite early on. My friend fell pregnant a month before us, and when we discovered we were both having the same gender baby - name issues arose. We wanted to say - look we're calling our LO ****, but she didn't want to know - her opinion was if they chose the same name (they hadn't picked a name yet), then it was our problem.
I mean it all seems a bit daft looking back, and we did end up just telling her our kiddos name. I think me and my OH were just so wound up about it because it was a name we had picked for a long time and had always hypothetically called our future child this name.
But like, yeah... no help. But ultimately, I suppose in your situation i'd have regretfully changed the name and been devastated about it.