In addition to using the swap command to change the focus of your session from one screen to another, if you are running the ISPF Client/Server you can use the SWITCH command to change the way the screen is displayed, either GUI mode or 3270 mode.

From any GUI screen you can enter the command SWITCH 3270. The GUI screen disappears and the screen is then displayed full-screen on your 3270 display. The 3270 screen is now operational. If you had been in split screen mode, the remaining GUI screens remain in GUI, but are disabled. To swap back and forth between the GUI and 3270 sessions now, you must use the SWAP commands (SWAP x, SWAP LIST, and so forth). The SWAP LIST panels ISPSLIST and ISPTLIST have a field indicating the session type (GUI or 3270).

If you want to switch your 3270 screen back to GUI mode, enter SWITCH GUI on the command line.