Dawn is at Lake Verity.
You can find Dawn at Professor Rowan's research lab in the Sinnoh region.
Professor Rowan was not released for leaf green.
Prof rowan is only in diamond and pearl and platinum.
You can find professor Oak, in Pallet town for older Pokemon games. For most of the Pokemon games there isn't any professor oak you can only find professor Rowan in Samage town.Usually in some places in the Pokemon world, you can find Dawn in front of one of the places were one of the professors work.
just find what you have to do and he will come
you get it from professor rowan after you get the national pokedex
Dawn can be found in Sandgem Town in front of Proffesor Rowan's lab
In his lab
professor rowan doesnt have a lab in eterna but oak stays in a house north west of eterna once u finish the national dex
Professor Rowan's lab is in Sandgem Town, which is north-east of Twinleaf Town. Hope this helps! :D
You talk to Rowan in his lab then he will give it to you.
profesor rowan does not hav a dasugher you genius