Is it possible to move messages from unacked state to an active state?

Unacknowledged messages are those which have been delivered to a consumer, but have not yet been ack'ed or nacked/rejected, and where that consumer hasn't yet closed the channel or connection over which it originally received them.

The broker can't figure out if the consumer is just taking a long time to process those messages or if it has forgotten about them. Therefore, you will not be able to move from status unacked to active. You can, however, disconnect the consumer from the broker, which will force all un-acked messages from this channel to be put back into the queue.