EDIT: Thank you everyone who responded. My issue has been resolved but of course feel free to continue any discussions that arose from this topic
I have a character that doesn't get their name revealed to the reader until they introduce themselves to another character. They survived a car crash and I at first refer to them as "Man Who Survived" in the descriptive text each time they are involved in a scene. After they say their name to the other character, I then change their name above their next line of dialogue, and the rest thereafter, to their actual name. Do I need to write a piece of descriptive text before they say their next line of dialogue, that includes their now revealed name in all caps, or can I just leave it at making their next line of dialogue be under their now revealed name?
Aw crap, this topic is near and dear to my heart. Can't... escape... the tractor beam.
Your post falls directly in line with the good practice of
only writing what you can see. Plus the fact that you never asked "Is it OK to do this", but instead asked "How do I do this", tells me you already knew full well this is a frequent device. Nicely done.
It's a script. There is no need to hide anything in the script. Ever.
I find it hard to get behind that.
You should find it impossible. The first page of this thread is like a misinformation highway... that was iced over... with heavy fog... at night... during rush hour.
A wise screenplay reader (not writer) once said that good writing is distinguished by how well your exposition is disguised. And I can personally attest that bald exposition is a rampant problem.
So here we go...
If the audience hasn't really "met" the characters yet
and/or you want to maintain a bit of mystery then by all means you need to do this. It's routine to be honest, but admittedly takes more finesse and inventiveness.
One typical approach is to take the enigmatically named character along through your pages until another character calls them by name (or sees a business card or a desk nameplate or a drivers license or a variety of other creative reveals). Heck, now-a-days it's nothing for the trendy coffee shop barista to yell out the name of a character we (yes we the audience, you're always writing for the audience) don't know yet - or perhaps even slicker for us to see the name scrawled in black marker on their polyethylene-coated cup.
As far as format, assuming you've properly cemented their description over the course of their "unidentified" run, just put the former name in parens after the revealed name, and only do this the first time it happens. Like so...
====
Officer struggles to catch his breath.
OFFICER
How much further son?
Guide looks over his shoulder.
GUIDE
Just about there Sergeant Stardrinker.
Guide walks away.
SERGEANT STARDRINKER (OFFICER)
Well I do believe I no longer know where "there" is. In fact I'm not sure of where "here" is. How about we...
Sergeant Stardrinker is interrupted by the sound of sliding rocks. He looks around.
SERGEANT STARDRINKER
Mr. Darkbloom?
MR. DARKBLOOM (GUIDE) glides down a sloped embankment on the opposite side of the plateau.
====
Now I get the impression that this may be a fresh concept to some and I totally understand the whole sake of simplicity thing can seem really freaky, but it's a non-issue on all fronts (except perhaps the challenge it may create for some writers). In my experience actors are typically pretty jazzed to know they are "two" characters in one and have no issue keeping this straight if they know their characters story (which they will, eventually better than you). Readers of course love suspense and surprises, in any form, but I already covered that. As far as script management, it's nothing really. If you have a great story that enthralls and excites the cast/crew then running reports or creating shooting scripts or blocking scenes that have "DRIFTER" and "BUTCHER BAKER" (the former Drifter) in them will be immediately embraced and easily absorbed by all parties involved. All of that being said I would definitely modify your example from MAN WHO SURVIVES to just SURVIVOR.
The practice of a character being THE STRANGER for 10 pages before a ranch hand recognizes them on a wanted poster, or a WAITRESS pouring a dozen cups of coffee before a patron reads the name tag on her uniform, or a PROWLER killing every single camp counselor before being called JASON is commonplace in good screenplays.
OTOH to poof a SUGAR KANE KOWALCZYK into the middle of an action scene without warning is uncouth, furthermore to write "A SEXY MUSICIAN, let's call her SUGAR KANE KOWALCZYK" is unforgivable.
After all this is what we will see, and only what we will see.