See who you’re sharing a calendar with on iCloud.com
Any iCloud user who is a participant in a shared calendar can see the responses of the other invitees.
In Calendar on iCloud.com, click the Share button to the right of the calendar’s name in the sidebar.
In the Calendar Sharing window, view the icon next to the name of each invitee:
The invitee has joined as a participant.
The invitee declined the invitation.
The invitee hasn’t responded yet to the invitation.
You can resend invitations at any time.