I've typed this into google and it seems to be believed that the change came after an ambassador went over to Nazi Germany and was convinced due to being a cognate of the word Aryan, which signalled they were an Aryan race.
Is there much truth to this? Was it even a consideration? Or was it just because the Persian word for Persia is Iran?
Iran has always been called Iran by natives. Refer to this post where someone asked the same question 5 years ago.
Also Aryan was a term stolen by Nazis from Indo-Iranians who settled in ancient India and Iran.
The word Persia was to call dynasty of Persians that rule over the multiple Empires and it is language of Persian ethnic's that then become official language of many empire's,a lango-franka-how ever the land it self wasn't called Persia by the people and it always was Iran( Eran, Eran shahr) Beacuse of kurds baloch gilak mazani ..... was part of Empire population that all were Ianian people and language of them were Iranian as well and there where some population (minority back then) of arabs, armenian , turks ,syrian , indian and hebrews that effect languages and writting system. so the name of Empire since Partian and Persian sassanid was Empire of Iranian and Aniranian(non Iranian) with arab invasion and colapse of sassanid dynasty empire the the land called persia or in arabic fars but sure that persian was dominate language at past with this after 900 years safavid dynasty renamed persia to iran . with the official language being persian having diffrent ethic groups empires again and thus the land by people itself called iran and by non iranians called persia and with renaming iran to persia by infamous qajar dynasty reza shah(king) officially renamed persia to iran and it was recognized by countries at that time