Mismatch of form 16 and 26AS

case1: If there is a mismatch in form 16 and form 26AS regarding salary and TDS,salary and TDS given in form 16 is correct ,then what to do in that situation? case 2 : If the employee has worked in 2 company during the previous year , TDS and salary of the past past employer is reflected in form 16 but it's not showing in 26AS then what to do in that situation?