There are two ways to get into the Channel editor:

1) From the experiment summary view, scroll down to the list of files.  Next to each file it will list the Staining Panel assignments.  Click the Staining Panel to edit Channel names and Staining Panel assignments.  

2) From the illustration view, click the "Edit" button within the "Channels" dimension.  

Note that the Channel editor and the Staining Panel editor are combined in Cytobank.

Once you have opened the Staining Panel and Channel editor, you will see two sections.  At the top is a section for file categorization.  At the bottom is a list of the Staining Panels and their Channels.  

To rename an existing staining panel, click the name of the panel in the blue box, and the field will become editable. Likewise, to change the name of a channel, click inside the corresponding box under the Reagent heading and enter a new name for the reagent assigned to that channel.