As an Administrator, you'll have an Inbox for the call specific messages/notifications. When there's a pending/unseen message or notification, you will have a number alert next to the Inbox tab.
Here you can find the following type of notifications:
A Reviewer has recused to review a submission, from here you can confirm the Reviewer's name, a direct submission link, you can immediately reassign the submission to another review and confirm recusal.
Incoming Submission Transfer Request
When transferring a submission from one call to another, you are required to accept/decline this transfer from the Inbox.