SpiritualFamily.Net

Jesus is called Michael and Michael is called Jesus. They are one and the same... I don't know about names over there, but particularly with men here, after they grow up and begin working they lose their childhood name and use their formal name.  Example: boys called RICKY when younger become RICK when older, boys called STEPHEN as a boy, become STEVE as an adult, boys called ROBBIE here become ROB or ROBERT, etc. So, if you just think of Jesus as Michael's name when he was in his lowest form, a human, here on earth, then returned to his formal and official status as Michael, our Creator. But he will always be Jesus to us!

Has to do with his ROLE: as Jesus, he was one of us, learning everything there was to know to be a human being on this world...and he did it perfectly.   As Michael, he created his whole universe along with his female partner, the Divine Mother.

I found also the answer on Urantia Foundation website.
https://truthbook.com/frequently-asked-questions-faq/faqs-about-jesus/are-archangel-michael-and-jesus-the-same/