Editing and Correcting Dictation; i.e., Backspacing

I am not visually impaired, but I was using the dictation function in email on my Mac Pro.

How do I backspace when the dictation function is turned on. i.e., if I want to make a

correction. I tried using words like "back" or "go back" to see if the keystroking would go

back, but it does not.

Pls help.