I am wanting to set up a workflow that will send out an alert a number of days/hours BEFORE a date.

I have a field (due completion date) which, when a project is started, is populated with the completions date.
I would like to receive an email 3 days before the completion date to remind me that the date is looming, but cannot get a workflow to work.
The nearest I have gotten is that in the workflow I can set up a schedule for "3 days before now" but the NOW in question relates to the SAVE date, and not the date in due completion date field.

Is this possible?

Spiff