A Sefardic Jew with an Ashekenazic Rabbi and an Ashenazic Jew with a Sefardic Rabbi

Q: Can a Sefardic Jew have an Askenazic Rabbi or an Ashkenazic Jew a Sefardic Rabbi?
A: It does not matter. The person certainly has to tell the Rabbi that he is Ashkenazic if the Rabbi is Sefardic, and the Rabbi will answer him according to what an Ashkenazic Jew is should do. A Rabbi knows the halachah for everyone, and if he does not he will ask, except is the case of "pikuach nefesh" – a life threatening situation, since "piku'ach nefesh" is the same for a Sefardic and an Ashkenazic Jew.