How to convert date to mm-dd-yyyy without time stamp?

Question

I have this date: 2016-06-24 00:00:00 and I want to convert it to mm/dd/yyyy (no time stamp)

I tried this:

data$PSDate <- as.Date(data$PSDate, "%m-%d-%Y")

but get this error message: do not know how to convert 'data$PSDate' to class “Date”