Write MDX query to retrun sales for previous day

Is there a a way to write an MDX query that will return data for the previous day.

my fact is [Measures].[SalesOrderAmount]

and my date dimension is  [Date].[Fiscal].[Date]

I need something like this:

SELECT [Measures].[SalesOrderAmount] on Columns
FROM [MyCube]
WHERE [Date].[Fiscal].[Date].&[yesterday]

Is there a way to determine yesterday's date?

John Schroeder