BeeDeeDubbleU - 7:02 am on Apr 2, 2010 (gmt 0)
In my experience doing what the OP suggests will almost certainly cause no problems. I have information based websites that I make minor changes to infrequently and AFAIK this has never damaged my rankings. Even a full rewrite of the page content should not cause problems provided that the keywords are retained in all the right places.
Also, if the page's ranking comes mainly from off page factors then clearly you can get away with even more.