SQL OR with MDX

I have a Measure called Supplier Number in the cube. The Supplier table acts as a Dimension as well as Fact table in the Cube. There are two dimensions - CreationDate and Modification date that are linked to Supplier fact table.My requirement is to get the Supplier Number which got Created (CreationDate) or which got modified (Modification date) for any current month selected. How to achieve this in MDX? Hint: This is like a SQL OR condition with CreationDate and Modification Date.