local function format_date(y, mo, d, h, mi, tz)
    local f = "%B %d %Y %I:%M%p " .. tz
    local tm = os.time({year = y, month = mo, day = d, hour = h, min = mi})
    return os.date(f, tm):replace(" 0", " "):replace("AM", "am"):replace("PM", "pm")
end

local months = {
    "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
}

local date = "March 7 2009 7:30pm EST"
print($"Original date/time : {date}")

local fields  = date:split(" ")
local fields2 = fields[4]:split(":")

local mo = months:findindex(|m| -> fields[1] == m , 1, true)
local d  = tonumber(fields[2])
local y  = tonumber(fields[3])
local h  = tonumber(fields2[1])
local mi = tonumber(fields2[2]:sub(1, 2))
local ap = fields2[2]:sub(3, 4)
local tz = fields[5]
if ap == "pm" then h += 12 end
if h == 12 or h == 24 then h -= 12 end

-- Time and date 12 hours later
local date2 = format_date(y, mo, d, h + 12, mi, tz)
print($"12 hours later     : {date2}")

-- Switch to MST time zone which is 2 hours earlier than EST.
local date3 = format_date(y, mo, d, h + 10, mi, "MST")
print($"Adjusted to MST    : {date3}")