過則勿憚改 [过则－惮－]

Jyutping gwo3 zak1 mat6 daan6 goi2
Pinyin guò zé wù dàn gǎi

Definitions (Wiktionary)
  1. phrase, idiomatic
    do not fear correcting one's mistakes when they have been made
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）