Microsoft Word// Calculating a date based on a REF Field // SUM

Hi

I enter date on the first page of the document.
November 15, 2008
The name for this field is "DATE" [For more information please see http://gregmaxey.mvps.org/Repeating_Data.htm ]

Now i have lot of REF fields in the document that use this field.

I need to create another date which is based on the calculation of 30 days to this date. e.g
New Date = November 15, 2008 + 30 = December 15, 2008

How can i accomplish this without using Macros ? I have never written a macro and do not know abou their usage. I tried this
{=SUM( {Date}+30)}. I get syntax error.

Help is very much appreciated.

Thanks.

iCeb.