In the first part of the study, you will be assigned to a dose level of azacitidine based on when you join this study. Up to 2 dose levels of azacitidine will be tested. At least 3 participants will be enrolled at each dose level. The first group of participants will receive the lowest dose level. The next group will receive a higher dose than the group before it, if no intolerable side effects were seen. This will continue until the highest tolerable dose of azacitidine is found. This is called the Dose Escalation Group.