Could anyone please let me know of using "in" and "available" mean the same in the sentence below? It strikes me as if "in" is less formal than "available".
Helen: Midtown Computer Solutions, Helen speaking. How can I help you?
Ryan: Hello, this is Ryan Bardos. May I speak with Natalie Jones, please?
Helen: One moment please – I’ll put you through.
Helen: Mr. Bardos? I’m afraid, she is not ........ at the moment. Would you like to leave a message?