To rename a Switcher-created video within the app, start by tapping the Home Screen Menu, the icon in the upper left (looks like three horizontal lines).
Next choose, My Recordings.
Tap the video thumbnail you wish to rename.
Tap Rename at the bottom right of the popup menu.
Give your video a new name, and tap Rename when done.
You can return to the videos listing by selecting My Recordings in the top-left of the screen.