Calendar calendar = Calendar.getInstance();

  calendar.set(Calendar.MONTH, 1);
  calendar.set(Calendar.YEAR, 2013);
  calendar.set(Calendar.DAY_OF_MONTH, Day-7);

  calendar.set(Calendar.HOUR_OF_DAY, 0);
  calendar.set(Calendar.MINUTE, 0);
  calendar.set(Calendar.SECOND, 0);
  calendar.set(Calendar.AM_PM,Calendar.AM);

  Intent myIntent = new Intent(MainActivity.this, MyReceiver.class);
  pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, myIntent,0);

  AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
  alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);

AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
  alarmManager.set(AlarmManager.RTC_WAKEUP, (calendar.getTimeInMillis()-(no. of days * 86400000)), pendingIntent);

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.MONTH, 0);
calendar.set(Calendar.YEAR, 2014);
calendar.set(Calendar.DAY_OF_MONTH, 4);
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
long eventTime=calendar.getTimeInMillis();//Returns Time in milliseconds

long oneDay=AlarmManager.INTERVAL_DAY;//Converts 24 Hrs(1 Day) to milliseconds
int noOfDays=4
long reminderTime=eventTime-(noOfDays*oneDay);//Time in milliseconds when the alarm will shoot up & you do not need to concider month/year with this approach as time is already in milliseconds.

//Set alarm
Intent myIntent = new Intent(MainActivity.this, MyReceiver.class);
pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, myIntent,0);
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, reminderTime, pendingIntent);