So, you need to lower all prices - i.e. as an exporter you ask your workers to take wage cuts, they must ask their landlords to reduce their rents, shopkeepers

So, you need to lower all prices - i.e. as an exporter you ask your workers to take wage cuts, they must ask their landlords to reduce their rents, shopkeepers to reduce prices etc. This is a slow process (especially because many contracts run for a fixed period so cannot be changed until the next contract is signed). Internal devaluation can be done, it is just a slow and painful process (usually including higher unemployment).