How to ALTER multiple columns at once in SQL Server

I need to ALTER the data types of several columns in a table.

For a single column, the following works fine:

ALTER TABLE tblcommodityOHLC
ALTER COLUMN
    CC_CommodityContractID NUMERIC(18,0) 

But how do I alter multiple columns in one statement? The following does not work:

ALTER TABLE tblcommodityOHLC
ALTER COLUMN
    CC_CommodityContractID NUMERIC(18,0), 
    CM_CommodityID NUMERIC(18,0)