Have a nice day.
"-and we would like to see you join our staff." The headmistress ended her persuasive speech, giving a small, hopeful smile to the young man sitting on the other side of the desk.
Harry, on the other hand had been patiently waiting for the headmistress to end, all the while thinking how to phrase declining the offer politely. The smile that she gave made him wince, knowing very well that it was a rare occasion, a different job he'd heard other students getting. With a shaky from nerves hand he'd pulled at the hem of his robe, taking a deep breath and looked up, straight in her eyes and shook his head: "I'm sorry to refuse, I rather not."
She raised her eyebrows, not quite understanding: "Are you sure Harry?"
"Really madam, I'm flattered but I'll have to decline. I have, uhm, my own course set."
"I surely remember last coaching interview where you'd said you have no plans. I must press the matter that leaving Hogwarts without future plans isn't allowed, for those students there is a job available until they have made a choice. I am under the impression I could include you into that specific group."
"Even if that's so, I am still humbly declining madam," Harry said and stood up, extending his hand: "I'm sorry for wasting your time, I'm not interested, because, I do have some plans you see," He bowed slightly: "I merely do not agree upon the order of sharing them, they're just not to your concern."
The headmistress stood as well, the small smile long gone and shook the black-haired wizard's hand displeased: "Very well Mister Potter, not sharing may result in you not leaving but, for now I cannot say more than good luck. We shall proceed this discussion another day."
"I'll like to see you try but I don't think so. I'll stand my ground upon keeping my secret," Harry answered when he heard the threat and smiled; "Thank you and have a nice day."