Within Teamwork Chat, you can update the settings for a project channel and update or remove the associated project.

When viewing your project channel, select the settings tab at the top of the pane on the right hand side and click 'Edit channel':

Changing the associated project

In the edit channel modal, you can select a different project from the projects dropdown:

Note: Once a different project is selected, the channel members list will be updated to only include users on the newly selected project.

Unlinking a project channel

You can also unlink a project from a project channel, reverting it to a regular chat channel.

In the edit channel modal, toggle off the 'Link this channel to an existing Teamwork Projects channel' option, and click 'Update' to save the changes:
For more information, see: Creating a project channel