The Board of Education of the Azusa Unified School District this week is interviewing candidates to fill a vacancy on the board. Someone will be chosed to compete the term of David Evans, whose resignation took effect last week. Evans, who was appointed to the board in 1980 and elected in 1981, cited personal reasons when he made the surprise announcement of this resignation. His term will expire in November. His replacement will take office 30 days after appointment.