Hi Satish,
Please use the below statement to reset the password
brconnect -u system/<password> -f chpass -o sapsr3 -p <password>
Select the profile SELECT profile FROM dba_users WHERE username = 'SAPSR3';
alter the profile and make sure the password is not expired by using the below statment.
ALTER PROFILE <profile_name> LIMIT PASSWORD_LIFE_TIME UNLIMITED;
regards
kartik