Currently in outlook add-in (Smart Calendar) displays user's last name instead of user's first name or full name.
In our exchange level, our display name saved in the format of Lastname, Firstname and i understand that Condeco add-in picks up and display the first part of the display name base from the exchange settings.
I spoke with our exchange team and was advised that it is not possible for them to make this change due to dependencies.
Therefore, your support team has advised to raise this suggestion to make a code level change on add-in to display the user's full name or if possible to display the second part of the name which is the Firstname.

Related case ticket - 287404