How can I delete an account from Windows 10 Calendar?

[Windows Central Question]

I have Windows 10 and want to start using the calendar app. The problem is that a few weeks ago a friend wanted to use Cortana and singned in with his account. When starting the Calendar app I am unable to delete his account.
I cannot submit a screenshot of that.

 

[realwarder]

Settings (gear), accounts, select account, remove.

 

[gues1]

I do not have that option.