改天 gǎi tiān 改天 means another day, and refers to a day in the near future. It’s a phrase to use when one wishes to do something in some other time. For example: 改天我打电话找你，把故事给你讲完吧。 (Gǎi tiān wǒ dǎ diàn huà zhǎo nǐ, bǎ gù shì gěi nǐ jiǎng wán ba) I will call you another day, and will tell you the whole story. 我愿意去，可是现在有一点儿忙，还是改天吧。(Wǒ yuan yì qù, kě shì xiàn zài yǒu yī diǎn er máng, hái shì gǎi tiān ba) - I want to go, but I’m busy now, I’d rather go another day. 时间不早了，我们改天再喝一杯吧。(Shí jiān bù zǎo le, wǒ men gǎi tiān zài hè yī bēi ba) - It’s getting late, let’s have a drink again another day.