Webdav change one instance of recurring appointment

[agruzglin]

I have an outlook calendar, in which I am successfully inserting recurring appointments. What I have not been able to do thus far is to change programmatically the time in one instance of the recurring appointment. So for example, I have a sequence on mondays and wednesdays 1-1:30, and I need to programmatically change the time on one of the days to 4-4:30. I have searched numerous groups and have not
been able to find anything. How should this be done? Please help.