Channels are managed by admins and amplifiers via the 'Manage Channels' page found through the easy access bar on the left of the page.

In the 'Manage Channels' page, you can see 'Active Channels' (either on-going or fixed-time currently running) and 'Archived Channels'.

A channel becomes archived when its fixed date has expired. It’s not deleted straight away, it will simply move from the 'Active' channel list to the 'Archived' channel list.
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To reactivate it, just click the 'Edit' icon on the right-hand side of the selected channel.

From the edit menu you can change the start and end date of the channel to make it active again, or even turn it into an on-going channel. You can also change the channel name, its owner, members, and its targets.