You can quickly view your Sent Emails, Scheduled Emails and Scheduled Campaigns two ways:

From your Dashboard: select the Scheduled Emails or Scheduled Campaigns tab.

OR, go to: Reports > Emails > Email History

Within your Sent Emails tab you are able to filter by Time Period and Sales Representative:

Click the Scheduled Emails tab to cancel or reschedule individual email templates:

Click the Scheduled Campaigns tab to cancel or reschedule a Campaign: