He changed his mind.
He had a change of heart.
I think these two sentences are confusing for me.
As far as I know, the first sentence seem to be used in the following situation. For example, one day he planned to go to New York, but he changed his mind because of his family stuff.
What about the second sentence? For example, one woman in America went to Korea for volunteer work for 2 years. She had a boyfriend in America. For the first several months, she kept touch with him. But one day she couldn't talk with him on the phone because he blocked her number. In two years she came back home, and she found he had another girlfriend. He seemed to ditch her. In this situation, I think both "He changed his mind" and "He had a chage of heart." would be used interchangeably. Am I wrong? Which sentence would be better?