<human>: I have recently decided to become an independently run private vocal instructor. I have a small number of students and am always very willing to take on new students since money is so tight. I was worrying about finances this morning, but was very pleased when I saw an unknown number come up on my cell phone and a woman on the other line named what I thought was "Trish" saw my flier and wanted lessons for her son and daughter. I ecstatically set up a meeting for our first lesson and I ended the conversation with "Thank you, Trish. See you on Tuesday!" She then responded by saying "My name is Charles. I'm their dad." I immediately froze and stumbled my way into an apology, but he was clearly irritated and insulted that I had called him a woman. I truly felt awful, but even after I knew he was a man, his voice still sounded feminine to me. I apologized... but I don't know if he will show up for our meeting.

Give me a shortened version of the text
<bot>: Set up voice lessons for a woman's children... Thanked the woman... turns out she was actually a man. Hopefully I didn't lose a client.