If you live in Los Angeles (or nearly any major metropolitan area) you’ve seen the handmade signs stapled to telephone poles that say ‘Lose Your Accent!’ or ‘Accent Reduction!’ followed by a phone number where you can purchase lessons.
But guess what?
There is no such thing as ‘Accent Reduction.’
Learning to speak in an accent other than the one you arrived at naturally is an acquired skill. It is something that is added to your list of abilities, not something that erases an ability you already possess.
Think of it this way—when you were a little kid, and you learned how to skip or to jump, did you give up walking? Did the skipping or jumping ‘erase’ your ability to walk? Of course not. You walked when it made sense to walk, and skipped or jumped for enjoyment or to get over an obstacle. To this day you still know how to walk, skip, and jump and you use each of them as they seem most appropriate.
Even if it were magically possible that learning a new accent could ‘erase’ the one you naturally have, as an actor why on Earth would you want to do that? It would only make you eligible for fewer roles.
For the record, the appropriate term for learning a new accent is ‘Accent Acquisition.’
That said, please forgive your agent, manager, or acting coach if they toss around the term ‘Accent Reduction.’ They’ve probably just read a whole lot of telephone poles…