I'm sure that most cousins realize that any time they meet a person with the family name Dalfen, they are meeting a relative... perhaps a distant relative, but a relative non the less. This is because the original name of the family was Chalfen, and it was changed in Romania only several generations ago when the letter "D" was substituted for the letters "Ch" or the Hebrew letter "chet" which could not be pronounced easily by the non Jews in Romania. Some say this change was made because this branch of the family was in business and they wanted to make sure that the non-Jews would be able to pronounce their name.
In early 1973, when I was living in the Kiryat Yovel suburb of Jerusalem, I had a very interesting experience. A new family moved into our condaminium, and the name they posted on their mail box was "Chalfen" in Latin letters, and in Hebrew, the letters "Chet" "Lamed" "Pheh" "Noon". Suspecting the young man, Yuval Chalfen, is probably a very distant relative, I asked him where his parents came from? "Romania" was the answere.
I introduced myself to Yuval and when I said my name is Dalfen, he said he was familiar with that family name. He told me that an elderly aunt of his had once told him that a branch of their family in Romania, had changed their name from Chalfen to Dalfen.
Yuval also told me that his aunt told him that originally in Spain, the family was much larger and that in 1492 when the Jews were expelled from Spain, those members of the family who chose to go to North Africa, went by the name of Chalfon (a common family name now in Israel) and those who immigrated to other countries in Europe, went by the name of Chalfen.
We both decided that we were going to meet with his aunt to find out more about our families, but before we got around to doing anything, the Yom Kippur war broke out and this nice young man hurried off to join his tank crew in Sinai. He never came back! I miss him.