How to edit an embed?

I cannot edit an embed that is already posted, here is my code :

const c = client.channels.cache.get('919237216692215829')
const m = c.messages.cache.get('919675014633095179')
const embed = new MessageEmbed()
//embed..
m.edit(embed)

console:

m.edit(embed)
  ^

TypeError: Cannot read property 'edit' of undefined```