You can connect and disconnect as many email addresses as you'd like.
To connect new email addresses to Salesflare, go to "Settings" > "Email settings". Click on the large orange "+" button at the bottom right of the screen to add a new email address (it might be behind the support chat window).
To disconnect existing email addresses on Salesflare, go to "Settings" > "Email settings" as well. Click on the "Disconnect" button on the email address you wish to disconnect.