People say you can't, but you CAN make HM moves remove.
You must go to to the move deleter (don't know anymore which town/city)
and then select the HM move he would say that he can't delete that (HM) move!!
Then talk again to him and he will forget the HM move!!
The HM Whirlpool is not obtainable in Pokemon Platinum, for there is no use for it during gameplay.
Dig is not a HM in Pokemon Platinum but a TM, it can be found in the ruin maniacs cave.
in a Pokemon center
Select the Hm hit use and select Pokemon
In Pokemon Platinum, Flash is a TM.
you can get it in pokemon platinum!
its not an HM anymore you have to find it.
Surf is HM #3. :-)
steal other players flags, when you get enough you can remove boulders
its a hm and its called strength
The HM Strengt: You get it from Riley on Iron Island
at the city of the Pokemon league