Yes if you have scheduled an email campaign to go out then you can remove some of the recipient email addresses before the email is sent out.  To do this please follow the guide below: 

1. Click on the Marketing icon inside your account. 

2. The email campaign will be queued, meaning it will be scheduled to go out on the date and time you have specified in your Send LATER scheduling.   You will see the 'Queued' information as shown in the example below: 

3. You can  click on ‘Queued number’ (you need to click on the number and not the word Queued and it will popup a list of queue messages - see below)

This enables you to remove each individual email address from being sent the email campaign.