It's not that simple, because the option is greyed out (understandably, since there are no changes in a saved table)
But, you can do it.
Open SSMS, and select your database in the Object explorer pane.
Open the Tables branch, and right click the table you want to script.
From the menu, select "Design"
Make a trivial change (switch a "Allow Nulls" column to "Yes" and back to "No") or make genuine changes that you need to make.
DO NOT SAVE!
Now right click in the upper pane (not the pane with the "Column Properties" tab).
Select "Generate Change Script..." from the context menu.
You will be asked if you want to save this to a text file.
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
ALTER TABLE dbo.MyTable SET (LOCK_ESCALATION = TABLE)
Note that this doesn't contain full info on the table structure.
If you want full info in the ALTER script, generate a CREATE TO script instead, and change the instruction to ALTER manually.