If your meeting is 10AM Eastern, that's all you need. If your meeting is 10AM Dublin, that's all you need None of those timezones are half hour times. If you

If your meeting is 10AM Eastern, that's all you need. If your meeting is 10AM Dublin, that's all you need None of those timezones are half hour times. If you had a time at 10AM Delhi that would be fine too. Or 10AM Nepal.