You'll have to find another pupil.
4 seconds sound clip from the The Moon's Our Home (1941) classic radio play.
You can hear this line at 00:32:06 in the radio play.
Quote context
[...]
- Yeah, you're different tonight. Warm and human. Somehow all woman.
- Oh, it's been heavenly here. But I'm leaving tomorrow.
- Why not?
- Well, I have plans and, strangely enough, they all concern you.
- For instance? Well, for instance, I'm gonna teach you to ski tomorrow.
- You'll have to find another pupil.
- Well, now, wait. What makes you so determined?
- Something I'd almost forgotten.
- Oh. Oh, listen, that - that man you told me about in the carriage that day! Is he the reason?
- Maybe.
- Oh! Well, that - that... I feel better. Well, that's all settled.
- You aren't gonna marry him, you're gonna marry me!
- Well, is that a proposal or a threat?
[...]