Change the column name or datatype or size in sql server

How to change the column name of the table or datatype of the column or size in sql server


1)
How to change column name of the table in SQL

ALTER TABLE TABLENAME
             ALTER COLUMN [NEWCOLUMNNAME] varchar(200)


Example
ALTER TABLE tblUser
             ALTER COLUMN [Name] varchar(200)


2)
How to change datatype of the column in SQL

ALTER TABLE tblUser
             ALTER COLUMN [UserName] varchar(500)


3)
How to change size of the column in SQL

ALTER TABLE tblUser
             ALTER COLUMN [UserName] varchar(500)