(Edited) How to change TCP port on PX4

Sorry, I’m wrote my situation wrongly and edited the post. I’m currently trying to use PX4 on multiple simulators and I’m using AirSim simulator. I can change TCP port of AirSim simulator but cannot change TCP port of PX4. Because of this, I can only connect to one simulator. How can I fix this problem?

Which simulator are you on? for gazebo-classic, try one of these files: https://github.com/search?q=repo%3APX4%2FPX4-SITL_gazebo-classic%204560&type=code