Hello here are some examples. The original tones are the third tone for both characters, but in spoken Chinese, we will change the tone of the first character into the second tone. 3-3⥤2-3 老虎lǎo hǔ --- láo hǔ（tiger） 小姐xiǎo jiě --- xiáo jiě (miss) 雨伞yǔ sǎn --- yú sǎn (umbrella) But if you need to write down the pinyin for these words, the written version keeps same (the third tone)