Hi. If I write a crime jewel robbery, I am going to need people to have false identities. It would be difficult to have James Roberts [real character name JAMES] used in scene 8 and have him as Philip Cameron [False name PHILIP] in scene 12. Not confusing for me but would be for script readers and actors. I think the viewers would understand but the script editors may not.

Interesting concept !

MaybeI should pen at the top of the script stating that not everyone is the same as they appear to be.

I had a situation where one character was undercover for about half the script, and I can show what I did but remember it was only one character.

Princess Amity (dialog tag AMITY) inserts herself into a situation under the assumed name Aimee Adina.

During this extended period across different scenes, her dialogue tag remained AMITY but she was referred to in action as “Aimee” (with the quotes) and of course other characters referred to her as Aimee in dialogue.

This is assuming you want the reader to know exactly what is going on. Occasionally a writer will want the reader in the dark for a moment, such as introducing a character without immediately saying how important they are.

Okay I see what your doing but here they are in a bank as one person then in the house organising a ropery as another. It shifts backwords and forwards.
Kathleen and Suzan are mother daughter.  The thing is young Suzan has not been brought up to speed on the robbery yet. I suppose I should keep the real names as the names of the characters all through. Does this look okay?

SUZAN
Why exactly are we here mum?

KATHLEEN
There is something I would like to show you. Come over here.

They both walk through the public area.

FEMALE (V.O.)
(Shouting)
Kathleen.

KATHLEEN and SUZAN turn around to see JENNY ROBERTS (24) attractive slim blond coming towards them. She is posing as a Spanish lady GABRIELA DORANTES. JENNY and KATHLEEN hug each other and kiss on cheeks.

JENNY
(Speaking with a Spanish accent.)
Kathleen how lovely to see you. What are you doing over here in the states.

KATHLEEN
Oh we just came over to see this wonderful exhibition.
(Looking briefly at Suzan)
Oh this is my daughter Suzan. Suzan meet Gabriela.

JENNY
(Giving her a hug and a kiss on the cheek)
Nice to meet you Suzan. This is a nice exhibition isn’t it.

That's how I think it should work, but the usual advice of breaking up long sequences of dialog goes double for this situation. Use action blocks, even if they're not strictly necessary, to remind the reader which assumed identity is associated with which real identity.

You could refer to her in action as Jenny/Gabriela or simply "Gabriela" if you think it is obvious from context. I used the second form because it was only one character using an assumed name. If you are going to have multiple characters operating under false names, you might want to use something more explicit like Jenny/Gabriela.

Even if it's only one character at first, you will want to be consistent with how you handle this.

I'm curious how others here have handled situations like this.

I agree. There are four women who all have alternat identities scattered around the script. The reader would need reminding who is who when it happens. Love to here from othes on the forum.