Converting a date to an abbreviated month date

From my data set I converted the date into year-month-day, but now I want to format it to an abbreviated version for graphing purposes. So I want to take 2021-03-15 and turn it into March 15 for my graph I try to do this in my code with

NCM_tibble$date <- as.Date(NCM_tibble$date, '%b-%d')  

but it doesn't change the date. Here is what the dates look like

https://stackoverflow.com/questions/66809844/converting-a-date-to-an-abbreviated-month-date March 26, 2021 at 09:31AM