I created a variant of an email and sent to some constituents, but now I want to use the original message to send to all constituents. Will this constituent receive the message twice?
Email messages will only be sent to a particular constituent one time. If you select to send a variant of the message to the same group that particular constituent will be filtered out. You can verify this by calculating the audience and it will show users that have already received the message to be filtered out of the new delivery.