道歉信和感谢信.内容是某人请你吃饭你没去表示歉意.和某人请你吃饭你欣然前往,就行了.急用 高赏~

Dear XXX,(道歉并感谢)
Thank you for inviting me to your house for a dinner.I'm really appricate for that and would like to go.But I have a date on that day.So I'm sorry that I can join you.Thanks again for your hospitable inviting.
Best regards!
Yours Sincerely,
XXXXX
Dear XXXX,（感谢信——表示可以参加）
I have received your invitation letter.Thank you for inviting me to have the dinner in your house.I'm glad that you have still thought of me for a long time.And don't worry and I'll go there in time.
Thanks so much again.
Best wishes.
Yours Sincerely
XXXXX