What a curious expression:
"I changed my mind."
For one thing, was there ever a time when I didn't change my mind? Trying to not-change your mind is like trying not to think of a purple cow.
For another thing, and with no blah-blah reference to the spiritual folderol, who is this 'I' who changed this mind?
Maybe it's just one of those walking-around koans that leaves the 1,700 formal Zen koans in the shade. Or maybe it's just another piece of totally useless information.