"Turn off/disable game mode" is a common way to describe closing game mode in Engpsh.
This terminology comes from the computer and gaming industry where game mode refers to a setting that optimizes performance and minimizes interruptions for a better gaming experience.
Examples:
"Please turn off game mode on your device before starting the presentation."
"I need to disable game mode to take an important call."
Translations:
"请关闭游戏模式"
"我需要关闭游戏模式来接重要电话"