I am a big Beatles fan. And, you know, unbeknownst to anyone, I used to be one. But I have no problems of putting titles and lines from other songs in my songs, because they're great lines and great titles. ↗
A changeling is one child substituted for another. I couldn't find anything more apt. We had to kind of fight that supernatural element in the publicity, and I offered to try and find another title, but Clint liked it, and it stayed. ↗