Combination of quick keys to exit user session without closing it

[edieladio]

I have a Toshiba Satellite U400 laptop somewhat old. I have Linux Mint 19 Cinnamom installed. The computer has a problem with the connection to the screen so that sometimes moving the screen to adjust its inclination turns it white, and it is not possible to see it correctly by simply moving it. The correct functioning is recovered by switching off and restarting or also by pressing the Alt + Ctrl + Backspace keys: this way the screen is seen correctly again but the work that was being performed in the user session that has been closed is lost. My question is whether there is any way to exit the user session without closing it by some keyboard combination, so that when you return to that user session, what you were doing before leaving the session is maintained.
Thanks in advance