OPTION 1:
Create a date newInstance() and pass the Year, Month and Day from the dateTime.
DateTime dt = System.now();
Date d = Date.newInstance(dt.year(), dt.month(), dt.day());
System.debug('Print Date:' + d);OPTION 2:
Get date from the DateTime using Date() method.
DateTime dt = System.now()
Date d = dt.date();
System.debug('Print Date:' + d);