How to modify and add column in SQL Server’s table with TSQL

USE Arm_DB
Go
IF OBJECT_ID('TBL_Persons','U') IS NOT NULL
 DROP TABLE TBL_Persons

CREATE TABLE TBL_Persons
 (
   ID INT IDENTITY PRIMARY KEY
   ,NAME Char(50)
 )

GO

     ALTER TABLE TBL_Persons
     ADD Lname Nvarchar(70)
Go
    ALTER TABLE TBL_Persons
    ALTER COLUMN NAME NVARCHAR(50)
GO
    INSERT INTO TBL_Persons(Name,Lname)
     VALUES ('Arman','Nas')
GO
    SELECT * FROM TBL_Persons