SQL Server doesn't have command to add or remove IDENTITY property of a column. You can do it in SSMS. Generate a script before applying changes to see how it's done.

>
>I have a table, to which I add a column:
>
>alter table temp.dbo.tmpdumpallprs
> add dumpprsid bigint IDENTITY(1,1) NOT NULL
>
>So the column is filled with values 1 to {nr of records}. Now I want to add a constant to the column. So I have to remove the identity property. How do I do that?