Excel to add event on outlook calender
 

Is there a way to get excel to add an event onto an outlook calender?

My spreadsheet is set up to have a few possible fields, but i want when
'Annual Leave' is selected, an outlook calender all day event to be added.

Excel and outlook will be open at the same time so nothing needs opening.

Excel to add event on outlook calender
 

I have the macro now to add the event onto my calender.

Sub Add_Appointment()
Dim myOlapp As Object
Dim myitem As Object

Set myOlapp = CreateObject("Outlook.Application")
Set myitem = myOlapp.createitem(1)

With myitem
.Body = "Annual Leave."
'.Duration = dur'
.AllDayEvent = True
.Subject = "A/L"
.Save

End With

Set myitem = Nothing
Set myOlapp = Nothing

End Sub

What i now would like to know is:-

1) A code to run this macro if a field is changed, for example if a cell
between range b1 to b14 changes to A/L i want this to run and add the
appointment into my calender. This could also be done by clicking a button
after any updates have been made.

2) What field do i need to change to select the calender i want this added
to, i can get this to add to my calender, but eventually want it to add to a
shared calender.

3) Is there a way to only add new appointments, and not repeating the old
ones.

Thanks in advance