While a character in Beyond the Veil has a Max Psyche, they also want to keep their current Psyche above 0. If they fail to do this the character discorporates. While other effects may force, or allow, a character to discorporate, the effects are identical.
The player, and character, may remain where they are, however they should place both hands over their mouth to indicate their current condition. They cannot speak, trade, initiate challenges, use Powers (unless the Power explicitly says it may be used while the character is discorporate), or perform any other action except walking around.
Fortunately, a discorporate character can only be seen by other characters with no remaining Psyche, or that are using Powers that explicitly allow them to view discorporate characters. Also, a Discorporate character can enter their own Personal Demense even if other characters can see them.