How does someone modify someone's memory?
I have read a lot of parts in the books of Harry Potter where someone modifies someone's memory.
Obliviate - spell to wipe out someone's memory
I already thought of that spell, but I think that casting that spell will wipe the whole memory.
Tom modified the memory of Morfin and the House-Elf of Hepzibah
HP and the Half Blood Prince
Hermione modified her parents' memories that caused them to go to Australia
HP and the Deathly Hallows
Correct me if I'm wrong about my thoughts about the Obliviate Spell. Is there a certain spell that's specialized to modify someone's memory? If there is, how is its procedure? How does a wizard/witch modify someone's memory?