Brain Game: Anticipatory

Today's mentalfloss.com Brain Game Tuesday Test Time asks you to break down a nine-letter word, one letter at a time. Are you up to the challenge?

By removing one letter from the mix at each step,
and rearranging the other letters as necessary to form new words,
reduce the word "PROACTIVE" to the letter "O."

P R O A C T I V E
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _
_ _ _ _ _ _
_ _ _ _ _
_ _ _ _
_ _ _
_ _
O

Here is one SOLUTION.