Hi Sharath,
Can I ask why you want to update this directly in the DB as opposed to using the policy manager to do so?
It is not advisable to directly makes updates to the DB. Additionally, the passwords are encrypted.
If it is just an issue of a forgotten password you can follow this to reset it to 'password' so you can log in and change it.
Reset the credentials for the default Policy Manag - CA Knowledge
Regards,
Joe