If you have sent an email campaign and would like to send it to more recipients, you can do so through the contacts screen in Dynamics. You select the contacts which you would like to send the campaign to and click Send Email Campaign.
From here you can click on the Sent tab, filter the already sent email campaigns and select which one that you would like to send. You can use the eye icon to preview the campaign before the sending it.
Note: you can use advanced find to filter your contacts and create new views.
These contacts will now also be included in the reporting of that email campaign.
If you have selected recipients who have already received the campaign, Dynamics will recognise this and it will not resend the campaign to those contacts.