05:50, mirror hour

Five fifty is 05:50, and the reversal is clean: the five of the hour becomes the fifty of the minutes. A reversed mirror hour ten minutes before six, when the night has nearly run its course and the day is about to begin.

Five and five make ten either way round, and ten comes back to one, the digit a new direction starts on. A reversed hour is not a blank page. It is the same figures read the other way, which is what most changes are: nothing gets thrown out. Ten minutes short of six, the turn is already made.