How can I filter this data with a greater than date? I want only data greater than 8/1/2015. The date format for [$Survey].[Call Date]] is 2015-08-01 13:59:54

DRILLTHROUGH MAXROWS 1000000 Select ([Agent Information].[Site].&[Springfield],[Measures].[Survey Count])on 0
From [MyVoc SMS Survey]
RETURN [$Agent Information].[CSR]
,[$Agent Information].[Coach]
,[$Agent Information].[Manager]
,[$Agent Information].[Department]
,[$Survey].[Survey ID]
,[$Survey].[Call Date]]
,[$Customer].[Contact Number]

Can someone please help with this. I am used to using SQL, but this report is in MDX.