Modify password of an accnout in SQL Server

http://msdn.microsoft.com/en-us/library/ms189751.aspx

Create login sample:

CREATE LOGIN qa WITH PASSWORD = 'password01';
GO

Modify password of an accnout:

ALTER LOGIN qa WITH
PASSWORD = 'password01'
OLD_PASSWORD = 'password01';
GO

Then you should go to security folder on DB tree, right-click
this account, cancel 'enforce password policy', then you can
login. More details,refer to:

http://msdn.microsoft.com/en-us/library/aa337562.aspx