Change SQL Server Password Using SQL Script
Try this :-
Open the SQL Server Management Studio.
Open a New Query.
Copy, paste, and execute the following:
GO
ALTER LOGIN [sa] WITH DEFAULT_DATABASE=[master]
GO
USE [master]
GO
ALTER LOGIN [sa] WITH PASSWORD=N'NewPassword' MUST_CHANGE
GO
where NewPassword is the password you wish to use for the sa account.
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