Can you delete a sitemap & start all over again

all i want to know is can you delete a sitemap because i'm a newbie at
submitting sitemaps and i think i've messed up my first attempt. plus
the verification file can you use notepad? i tried notepad but it
would not allow me to save because of the long name google wants in a
nutshell i'm all at sea with sitemaps if anyone can help me i will be
grateful
pabsam