To mark the occasion, Macy’s will offer a double donation for all letters to Santa collected in stores and online at macys.com/believe on Fri. Dec. 11 NEW YORK, 2015-12-9 — /EPR Retail News/ — Magical wishes will be granted to children across the country with life-threatening medical conditions, as Macy’s and Make-A-Wish celebrate the seventh annual National Believe…