So you’ve got a character that has two identities… easy peasy.

Let’s start with the basic example:

Your character’s name is Fletch.

FLETCH     Do you think it’s a real gun?

Fletch goes undercover in a biker gang, where he’s known as MAD DOG. Wherever Fletch speaks where he’s referred to as Mad Dog:

FACE TATTOO     Nice wheels, Mad Dog. You sure you can handle all that power between your legs?

FLETCH (MAD DOG)     My Harley’s in the shop, the Vespa’s just a loaner.

I prefer parenthesis for alternate identities, because I like to reserve slashes for multiple simultaneous speakers.

FLETCH/JOE/MIKE     You’ve got to be kidding me!

If your character’s alternate identity is more than a mere name change, it usually makes most sense to simply state in the script (and or bible) the character plays two roles, and refer to the character as whichever character he’s representing at the moment.

JEKYLL     Don’t speak of him, don’t ever speak that name to my ears!

Later;

HYDE     London is mine!

An exception to this approach is if the character is frequently being referred to as both identities or the identity switch is more subtle, in which case it pays to stick with the parenthesis approach. ▪