How do I remove the in-call tab on the top of the screen during a mobile phone call?

[scb2371]

During a call, I like to play some games and explore the web, but while doing so there is a green tab with the call timer at the top of the screen and it won't let me rotate the phone screen to watch a video or play a game. Its in the way of the layout of the games and it's truly agitating. I understand it's a quick access button to the call you're currently in, but I rather not have it in the way of me doing things on my phone. Any possible way to remove this? My phone is a ZTE Warp 7 on Android 6.0.