On changing one's name

[O'Callaghan]

You might use "Tobus Kilpatrick Nee Englishname" on your typed signature line, the sign it "Tobus Kilpatrick"

A small point. For a man it would be ne, not nee (either one being lower case). It's French for born, a language that I assume you don't speak. And there is an acute accent on the first (or only) letter e, but I don't know how to type that.