Format Date/Time on Chart Y axis

I have a chart in a report with the y axis displayed using a datetime format. I want to change this to display the y axis with using the date only but the report config options only allow me to format the x - axis. There are a lot of forum questions on this topic but I can’t find any with an example for how to format the y axis by date. There are lots of references to the documentation but I’m having a hard time following the documentation to complete this task.

Can anyone provide some sample code on how to complete this specific task?