How do i call this function?

Im trying to call a function but it gives me this error:

“The name `quest’ does not exist in the current context”

here is me trying to call the function:
void Start(){
ShowQuestInfo(Quest quest);
}

and here is the function:

public void ShowQuestInfo(Quest quest)
{
//do stuff
}

private Quest quest;

void Start()
{
ShowQuestInfo(quest);
}

first of all use the Coding insert that this forum has. i assume u have a class called Quest? since Quest quest would be a DataType