M. Hansen is the manager of the offices of Oncology Partners of New Mexico.
Walter White came to the office to deposit a check, and Hansen accepted it from him. She told him to call if the discomfort of the treatments was too much, but that otherwise, they would see him in a week. ("Crazy Handful of Nothin'")
Some time later, Walt arrived again to receive a bill for his transaction. However, upon looking at the bill, he quietly asked Hansen about their arranged cash discount. Hansen assured him that it was included, and then gave him a button that read "HOPE: THE BEST MEDICINE". Walt accepted, but after leaving, he threw it in the trash. ("Breakage")