Who said "I have learned that change is the only constant."?

This quote is attributed to Missandei.

I have learned that change is the only constant. - Missandei

"I have learned that change is the only constant."

Missandei Change

"I am Missandei of Naath, interpreter and advisor to the Dragon Queen."

"Daenerys Targaryen chose to free us, not because she needed us, but because it was right."

"Knowledge is power, but wisdom is knowing how to use it."

"I have served many masters, but I chose to serve the Mother of Dragons."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."