the exchange web service (https://msdn.microsoft.com/en-us/library/office/dn509511%28v=exchg.150%29.aspx) offers methods for deleting (How to: Delete appointments and meetings by using EWS in Exchange) and updating (How to: Update appointments and meetings by using EWS in Exchange) appointments/meetings.
Thanks for your answer.
In call web service action,
I tried to enter url: https://ExchangeName/ews/exchange.asmx
After clicing on the refresh butten, I get unothorized .
what am I missing ?