I pushed an email campaign live yesterday that is a subject line test. I scheduled it so that it would declare a winner and send remaining emails on Monday. NOW I realized that Monday is right after Easter and this may not have been the best day to send the winner. Is it possible to amend the duration of the a/b subject line test even though the program is already running?
You will have to contact Marketo support to abort the send.
And then for next send, you can run a smart campaign to everyone who was not sent the AB test.
Depends exactly how the AB test was setup.