Use the "travessão" (—) for dialogue changes within the same subtitle block.
Use the "mesoclise" or "ênclise" sparingly to add a "classic" feel without making the text unreadable for younger Brazilians. Wilde Legendas Portuguese (BR)
Subtitle Edit (Free/Open Source) is the gold standard for syncing and translating. Use the "travessão" (—) for dialogue changes within