How is “if and when” used?

In Alita: Battle Angel (2019), one line is: “If and when you have pleased me...”

Which movie is “if and when” from?

The clip at the top of this page is from Alita: Battle Angel (2019).

If and when you have pleased me...

7 作品で登場 · 1 本目

イディオム

used to say sth about an event that may or may not happen

7 本の映画に登場

used to say sth about an event that may or may not happen
If and when we ever meet again I hope he remembers what I did for him.

定義：Oxford Advanced Learner's Dictionary 第 9 版