Switch to different app while in appium session

I want to switch to a different app B while I am in a test session of my "origin" app A. The purpose is to send data from app B to app A.

I already tried to restart my driver with different capabilities and I tried to have two different drivers in my test code. But none of that works.

Has anyone some suggestions how to achieve the switch? I'm working on a mac btw. Thank you in advance!