Can i remove hm attacks in diamond?

# Get to Canalave city. # Got to the house above the Poke'mart. # Go in. (DUUUUH!) # Speak to the old man. # He'll delete any move, including HM moves. * Don't forget the POKEMON. * You need Surf or, if you have already come to Canalave, Fly. * Hope that you'll have luck in teaching the PkMn (Pokemon) a move soon!