Hello & Welcome to JustAnswer. My name is Kamil and i will do my best to assist you.
Can you tell me which version of Outlook are you using?
Click File -> Account Settings
Select your account under Name then Click on the Change button above
Under Logon Information -> provide the new password.
Click Next and wait for the test to finish.
Let me know if that works.
Are you still there?
It appears that you are offline. If you have any problems doing this, please leave me a message and i shall provide a response soon as i return usually within an hour.