Email to Cindy
Dear Cindy,
Thank you so much for inviting me to go swimming tomorrow at 4:00 PM! I really appreciate it and was looking forward to having fun with you.
But I’m sorry to tell you that I won’t be able to go because I have a family event at that time. I really wish I could join you!
How about we go swimming together next Saturday instead? I am free at 2:00 PM if that works for you. Please let me know!
Thanks again, and I hope you have a great time swimming!
Your friend,
[Your Name]