HR_PERSON_API.UPDATE_PERSON -- mandatory arguments in correct

 I am trying to correct Date of Births of many employees we have - and running into issue using API. It says invalid mandatory arguments, i do not understand what i missing.I am now trying hard coded values...Here is the code it still doesnt work..what am i missing here?

declare

 P_VALIDATE BOOLEAN;

  P_PERSON_ID NUMBER;

  P_ASSIGNMENT_ID NUMBER;

  P_PETION_WARNING BOOLEAN;

  P_ASSIGN_PAYROR_OBJECT_VERSION_NUMBER NUMBER;

  P_PER_EFFECTIVE_START_DATE DATE;

  P_PER_EFFECTIVE_END_DATE DATE;

  P_FULL_NAME VARCHAR2(200);

  P_LAST_NAME VARCHAR2(200);

  P_PER_COMMENT_ID NUMBER;