ALTER IDENTITY COLUMN

I need to send this:

ALTER TABLE LMSBillHdr ALTER COLUMN LMSBillingID IDENTITY(1000,1)

Im wondering why that is failing, its bad syntax, but what is the good syntax for that?

from SQL server books online (T-SQL):

Code:

---

ALTER TABLE table
{    [ALTER COLUMN column_name
        {    new_data_type [ (precision[, scale] ) ]
                    [ NULL | NOT NULL ]
            | {ADD | DROP} ROWGUIDCOL
        }
    ]
    | ADD
        {    [ <column_definition> ]
            |  column_name AS computed_column_expression
        }[,...n]
    | [WITH CHECK | WITH NOCHECK] ADD
        { <table_constraint> }[,...n]
    | DROP
        {    [CONSTRAINT] constraint_name
            | COLUMN column
        }[,...n]
    | {CHECK | NOCHECK} CONSTRAINT
        {ALL | constraint_name[,...n]}
    | {ENABLE | DISABLE} TRIGGER
        {ALL | trigger_name[,...n]}
}

<column_definition> ::= { column_name data_type }
[ [ DEFAULT constant_expression ]
| [ IDENTITY [(seed, increment ) [NOT FOR REPLICATION] ] ]
]
[ ROWGUIDCOL ]
[ <column_constraint>] [ ...n]

<column_constraint> ::= [CONSTRAINT constraint_name]
{
    [ NULL | NOT NULL ]
    | [    { PRIMARY KEY | UNIQUE }
        [CLUSTERED | NONCLUSTERED]
        [WITH FILLFACTOR = fillfactor]
        [ON {filegroup | DEFAULT} ]]
    ]
    | [    [FOREIGN KEY]
        REFERENCES ref_table [(ref_column) ]
        [NOT FOR REPLICATION]
    ]
    | CHECK [NOT FOR REPLICATION]
        (logical_expression)
}


<table_constraint> ::= [CONSTRAINT constraint_name]
{    [    { PRIMARY KEY | UNIQUE }
        [ CLUSTERED | NONCLUSTERED]
        { ( column[,...n] ) }
        [ WITH FILLFACTOR = fillfactor]
        [ON {filegroup | DEFAULT} ]
    ]
    |    FOREIGN KEY
            [(column[,...n])]
            REFERENCES ref_table [(ref_column[,...n])]
            [NOT FOR REPLICATION]
    |    DEFAULT constant_expression
            [FOR column]
    |    CHECK [NOT FOR REPLICATION]
        (logical_expression)
}

---