In my screenplay my main character is talking to his sister on his cellphone. I don't want just her voice on the phone I want her in a separate space talking to him. That way it will go back in forth between his office and her bedroom.
does that make sense?
Every time they talk to each other the setting changes. how do you write it?

There are several ways, but my favorite is to use "intercut" in your slug line. This is taken from a BBC file on screenplay formatting.

INTERCUT - INT. LOCATION #1/LOCATION #2 - DAY

This, I think, is the easiest way to show a phone conversation.

CHARACTER #1
(into phone)
Here, you type your dialogue as normal.

CHARACTER #2
(into phone)
While indicating that both characters are on the phone.

CHARACTER #1
(into phone)
And then when the conversation is over, this is how you show it.
(hangs up)
Especially if you are going to continue the dialogue and scene beyond the phone conversation.

Hope this helps!
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Find the next word. Write it down. Repeat. Repeat. Repeat. --Neil Gaiman

Thank you I appreciate it. I was so confused on how to do it, this helps a lot thanks!