How to: Create a new date field based on a formula?
For example, let's say I want to calculate one month prior to an existing date. i.e. 6/1/15, month prior is 5/1/15.
To do this, I'll add a Formula tool to the canvas, connect it to your data stream, and use the DateTimeAdd() function.
Expression:
DateTimeAdd([Date], -1, 'month')
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