You can reset a passphrase for a client interview. For example, if your customer forgets the passphrase you can supply a new passphrase.
The passphrase button is not visible if you are using SMS code authentication.
The passphrase is reset. You must let your client know this passphrase, e.g. in a telephone call, so they can access the interview.
If you reset the passphrase to empty, the client will not be prompted to enter a passphrase.