Xiaoyu is leaving Auntie Wang's dinner. Chen Hao wants to see her out; she says no, it is cold outside.
Xiaoyu
阿姨，时间不早了，我先走了。
Āyí, shíjiān bù zǎo le, wǒ xiān zǒu le.
Auntie, it is getting late, I had better be off.
Auntie Wang
这么快？再坐一会儿吧。
Zhème kuài ? Zài zuò yīhuìr ba.
So soon? Stay a little longer.
Xiaoyu
明天还要上班，下次再来。
Míngtiān hái yào shàngbān, xiàcì zài lái.
I am working tomorrow, I will come again next time.
Auntie Wang
好。东西别忘了拿。
Hǎo. Dōngxi bié wàng le ná.
All right. Do not forget your things.
Chen Hao
我送你到门口。
Wǒ sòng nǐ dào ménkǒu.
I will see you to the door.
Xiaoyu
不用送，外面冷。
Bù yòng sòng, wàimian lěng.
There is no need, it is cold outside.
Auntie Wang
路上小心，到家给我发个消息。
Lùshang xiǎoxīn, dào jiā gěi wǒ fā gè xiāoxi.
Take care on the way, and send me a message when you get home.
Xiaoyu
好的。谢谢您今天的饭。
Hǎo de. Xièxie nín jīntiān de fàn.
I will. Thank you for the meal.
Auntie Wang
别客气，常来。
Bié kèqi, cháng lái.
Not at all, come again soon.
Xiaoyu
一定来。再见！
Yīdìng lái. Zàijiàn !
I will. Goodbye!
You do not announce your departure with a bare 我走了, which sounds like a walk-out. 我先走了 says "I am going first", that is, before the others and without presuming to end the evening. The expected reply is 再坐一会儿吧, which you decline once before actually leaving.
送 means to give, but also to see someone out: 我送你, I will walk you out. In China the host follows the guest to the lift or to the street, and the guest declines with 不用送. Both gestures are expected, and the refusal is as much a part of courtesy as the offer.
The phrase means "take care on the way" and is said to anyone leaving, whatever the distance. Its neighbours are 慢点儿开 to a driver, 一路平安 for a long journey, and 到了给我发个消息, which is today the commonest of them all.
