[R] Converting POSIXct format date to Character format

[e-mail ma015k3113]

I have a data frame "PLC" which has two variables Year_END_Date   EPS

YEAR_END_Date     EPS
2010-09-10        .10
2009-08-10        .20

When I tried to convert Year_END_Date to character format using

select(PLC, format(Year_END_Date,format = "%B %d, %Y"), EPS) I get an error

Error: Can't subset columns that don't exist.
x Column `Year_END_Date` doesn't exist.

I tried using 

PLC_1 <- select(PLC, as.character(YEAR_END_DATE), EPS)

I get the following error

Error: Can't subset columns that don't exist.
x Columns `2010-09-30`, `2009-09-30`, `2008-09-30`, `2007-09-30`, `2006-09-30`, etc. don't exist.
Run `rlang::last_error()` to see where the error occurred.

Can anyone please guide me what is happening and how can I resolve it?