at one's disposal(zhào zhī jí lái，huī zhī jí qù)

at one's disposal

Call to come, wave to go, call: wave. Wave: wave. I'll come as soon as I move, and I'll go as soon as I swing. I'm very obedient.

source

Chapter 6, section 5 of Lao She's Autobiography: "it's not polite to call on unimportant people and wave them away."

Examples

We promise to come as soon as we are called, to go as soon as we wave, and to obey the command absolutely.

Chinese PinYin : zhào zhī jí lái，huī zhī jí qù