I want to change a date in a field within my word document, and have it update a couple other fields automatically within the same document. The behavior I'm seeking is basically the same as what a spreadsheet can do.

Is this possible?

More specifically, if the first page of the document has the date Jan 20 2012, I want to be able to change it, and then watch a couple other dates elsewhere automatically change to either the same date or the same date plus six days.

I would also "settle" for having all three fields updated from a central document property (though I don't know how to create one of those properties). Regardless of which approach is used, I want one of the dates to be <value> plus six days such as Jan 26 2012 based on the earlier example I gave.