Call "launch as standalone mode" from customized editor

Dear community,

I already posted a question about an additional game mode. Since I didn’t get any answer I decided to do it in another way. I want to add a button inside my custom editor where I just only want to launch the game in standalone mode like the button in ue4 editor. Does anybody know how to do this? I don’t want to search through the whole engine I just hope anybody has some idea or experience with that.