Perform system maintenance unit running as it should. Homeowner had concerns of rattling in grill advised it was the louvers in the grill itself were probably loose trying to tighten up. The grill itself didn’t fix the issue. May have to replace grill also advised adjusting the damper for less airflow to accommodate the rattle she hears, homeowner stated she didn’t want to adjust dampers due to previously set by technicians that installed the unit and ductwork.