From USPS News Link:
Rutland, VT, Letter Carrier Christopher Greeno was delivering mail when he found a woman cornered by large, growling dog. The woman was visually impaired and used a cane to keep the dog at bay. Her guide dog was behind her. Greeno placed himself in front of the lunging dog and used his satchel to fend off the animal off until the owner arrived and restrained it. Greeno then helped the woman reach her destination.