Calendar item synced from microsoft outlook to galaxy s5- can't edit it?

[AMGS5]

I have seen old threads on this but have not seen an answer. I have a Galaxy S5 which I sync to my Microsoft outlook work email/calendar etc. When I enter a calendar event in outlook calendar and it syncs to my samsung I am not able to edit it. It comes through like an appointment and I can not edit it. Can someone help me? I would like to know how to have the item come through as an editable calendar event.
Thanks.