Change the platform without creating a new project

I do run PlatfromIO with ATOM on my mac and have created a project for a
board = lolin32
can I just edit the platform.ini file with what I need and recomple or how can I get this into a esp01_1m?

You can re-initialize your project (and IDE project files) with the correct board using pio init -b esp01_1m --ide=atom from the command line in the project directory. You can also directly edit your platformio.ini but you should do a re-initialization afterwards with pio init --ide=atom (for your IDE) to keep the IDE project in sync.