Changing first name to kanji

Hello!
Our baby is bicultural and was born in Japan. He has a katakana name. Is it possible to change the name into kanji? Name would be the same. Just change katakana to kanji!
Would be glad if somebody knows about this.
Thanks!

THough with the same sound, a Japanese name in katakana and the same sound written in kanji are considered to be two different names, so it may not be that simple.

- If the child is in Japanese "koseki" and you are talking about changing the name on "koseki," I believe it involves application to the family court.
- If the child is in "alien registration" in Japan, and you are talking about being able to use a kanji version of the name, so to say, *probably* you could go to the city hall and register an "alias" on the alien registration. But I'm not sure.