I will be selling my P4, how do I release it to the new pilot?

There's nothing to do on your end. The new pilot just needs to log into their DJI account in DJI GO and fly.

Be sure to format the micro SD card after exporting the files if you are giving it to the new owner as part of the package.

Hi there. thank you for reaching out. With regards to that. Yes right! no need to do on your end. You just need to tell that the second owner needs to create his/her own DJI Account to use it. Best Regards!