Change Column Type after loading with data

Hi,
I am using SQL Express from VS2010 (SQL 2010 R2)
I have a table with 2 DateTime columns and I would like to change there types.
Column1 from DateTime to Date (the conents are all dates with 00:00 for the time portion), Column2 from DateTime to Time (whatever dates can be dropped). I have tried going through the Designer and of course it fails...
Is there a quick method to change these column types?
SquireDude ...