The year before her family returned to China, in 1923, an uncle, Dr. Y. S. Tsao, then president of Tsinghua University of Beijing, had heard of the Baháʼí Faith through Martha Root and then joined the religion.
He translated Baha'u'llah and the New Era and Yen first heard of the religion through him.
She accepted the invitation of another uncle, Yan Huiqing, then Ambassador to the USSR, to serve as his hostess for events at the embassy.
She had some chance to address committees of the League of Nations through her diplomatic status – such as the status of women.
Through her extended activities away from her husband and children, the marriage was mutually ended.
At the end of their service, there was a party which included meeting Li Xiaqing and together they worked to make a presentation promoting Chinese women in flight.
She then served formally at the League of Nations for three years including working with committees addressing issues of trafficking in women and children in 1937.
Then she moved to the United States, took flying lessons and earned her aviator license.
With Li Xiaqing back in the States, they conceived a plan of flying from city to city from 1938 speaking about the spread of war and the need of assistance for China and boycotting Japan's aggression.
In 1939, a plane was donated – "The Spirit of New China" – which could use a copilot with Li and then Yen acquired her own plane also named "The Spirit of New China".
Yen's plane crashed May 1, 1939 outside of Montgomery Alabama.
Her injuries were severe but not life threatening.
Considering her situation miraculous considering the plane crash suggested the beginnings of a change in path for her life later to be realized.
Li finished their scheduled presence.
Yen was discharged May 11 and she continued her advocacy on land for a time before returning to air travel in another plane.
Her involvement in peace activities brought her into contact with Julia Goldman -she credits meeting Julia Goldman with re-introducing her to the Baháʼí Faith though it did not take her attention centrally for some years yet.
Events in China soon led to a return to China where her father served in the cabinet of Chiang Kai-shek.
In December 1941, she witnessed the marshaling of Americans after the attack at Pearl Harbor and as the Japanese arrived at Hong Kong while performing at a party for diplomats and Chinese leaders.
However, she made it out of Hong Kong on a cargo plane and eventually reached the United States.
Disappointed in politics and war, she was still passionate about peace and began flying again.
Through her increasing contacts with the Baháʼís, she asked to attend the 1944 Baháʼí Annual convention as an observer.
She was moved by the spontaneous gestures of welcome and care shown between individuals society normally kept apart as the material demonstration of the ideals of a worldwide unity across all humanity.
Then she requested to enroll as a Baháʼí.
She then asked to address the convention as a Baháʼí: 
"Fellow Baha'is, this is more than a pleasure.
It is a miracle that I am participating with you in discussing such important matters.
I contacted two denominations and a parliament of religions before I met Julia Goldman, Baha'i, who sowed this seed in my heart.
While convalescent from a flying crash, my life was given me for service to God.
Julia took me under her wing.
I saw God vaguely; then more clearly, through the Baha'i Faith.
Then came the battle of Hongkong(sic) where all shared in a common danger and hunger - forced to live the oneness of mankind.
At length I secured a priority to fly to America and how do I rejoice to be in this free country!
Conferring with Americans I have found this country the best to execute the message of peace.
I have been blessed in meeting other Baha'is.
I have been deeply impressed by the love and affection among Baha'is.
China is well prepared by its sages for the Baha'i Faith. …"

Her conversion was marked as a significant moment summarizing the religion in 1944 following on that of her uncle.
And she dwelt on the turning poi
The year before her family returned to China, in 1923, an uncle, Dr. Y. S. Tsao, then president of Tsinghua University of Beijing, had heard of the Baháʼí Faith through Martha Root and then joined the religion. He translated Baha'u'llah and the New Era and Yen first heard of the religion through him. She accepted the invitation of another uncle, Yan Huiqing, then Ambassador to the USSR, to serve as his hostess for events at the embassy. She had some chance to address committees of the League of Nations through her diplomatic status – such as the status of women. Through her extended activities away from her husband and children, the marriage was mutually ended. At the end of their service, there was a party which included meeting Li Xiaqing and together they worked to make a presentation promoting Chinese women in flight. She then served formally at the League of Nations for three years including working with committees addressing issues of trafficking in women and children in 1937. Then she moved to the United States, took flying lessons and earned her aviator license. With Li Xiaqing back in the States, they conceived a plan of flying from city to city from 1938 speaking about the spread of war and the need of assistance for China and boycotting Japan's aggression. In 1939, a plane was donated – "The Spirit of New China" – which could use a copilot with Li and then Yen acquired her own plane also named "The Spirit of New China". Yen's plane crashed May 1, 1939 outside of Montgomery Alabama. Her injuries were severe but not life threatening. Considering her situation miraculous considering the plane crash suggested the beginnings of a change in path for her life later to be realized. Li finished their scheduled presence. Yen was discharged May 11 and she continued her advocacy on land for a time before returning to air travel in another plane. Her involvement in peace activities brought her into contact with Julia Goldman -she credits meeting Julia Goldman with re-introducing her to the Baháʼí Faith though it did not take her attention centrally for some years yet. Events in China soon led to a return to China where her father served in the cabinet of Chiang Kai-shek. In December 1941, she witnessed the marshaling of Americans after the attack at Pearl Harbor and as the Japanese arrived at Hong Kong while performing at a party for diplomats and Chinese leaders. However, she made it out of Hong Kong on a cargo plane and eventually reached the United States. Disappointed in politics and war, she was still passionate about peace and began flying again. Through her increasing contacts with the Baháʼís, she asked to attend the 1944 Baháʼí Annual convention as an observer. She was moved by the spontaneous gestures of welcome and care shown between individuals society normally kept apart as the material demonstration of the ideals of a worldwide unity across all humanity. Then she requested to enroll as a Baháʼí. She then asked to address the convention as a Baháʼí: 
"Fellow Baha'is, this is more than a pleasure. It is a miracle that I am participating with you in discussing such important matters. I contacted two denominations and a parliament of religions before I met Julia Goldman, Baha'i, who sowed this seed in my heart. While convalescent from a flying crash, my life was given me for service to God. Julia took me under her wing. I saw God vaguely; then more clearly, through the Baha'i Faith. Then came the battle of Hongkong(sic) where all shared in a common danger and hunger - forced to live the oneness of mankind. At length I secured a priority to fly to America and how do I rejoice to be in this free country! Conferring with Americans I have found this country the best to execute the message of peace. I have been blessed in meeting other Baha'is. I have been deeply impressed by the love and affection among Baha'is. China is well prepared by its sages for the Baha'i Faith. …"
Her conversion was marked as a significant moment summarizing the religion in 1944 following on that of her uncle. And she dwelt on the turning poi
Hilda Yen