Would this work for you?
def overrideAlarmConfig(tagPath, alarmName, alarmProperty, value):
config = system.tag.getConfiguration(tagPath)[0]
for alarm in config['alarms']:
if alarm['name'] == alarmName:
alarm[alarmProperty] = value
break
basePath = tagPath.rsplit('/',1)[0]
system.tag.configure(basePath, config, 'm')
overrideAlarmConfig("[default]PT2323/PV", "Hi", "enabled", True)