How To Write A Letter To A Grandchild . Sample letter of consent for child to travel with grandparents. The great advantage of a legacy letter is that it can outlive a grandparent and possibly connect to generations that are yet unborn. Letter to my Grandchild by YiChieh CHUNG Issuu from issuu.com A letter to your grandchildren. Tell her that you miss seeing her or that you have been thinking about her. You’re feeling the vibrations of the outside world through your loving parents.