You might have faced a dilemma where you cant remember the SharePoint farm passphrase and now you cannot recall it.
Microsoft has given the option to change the passphrase. This can be done only using power shell and the account performs the action should have farm admin priviledges (Refer SharePoint Farm Service account in https://technet.microsoft.com/en-us/library/cc678863.aspx?f=255&MSPPError=-2147217396 )
Once its done Run PowerShell as Administrator and then execute below commands.
$passphrase = ConvertTo-SecureString -String “<AddNewPassPhraseHere>” -asPlainText –Force
Set-SPPassPhrase -PassPhrase $passphrase –Confirm
Hope this was informative.