Dear Mr and Mrs Smith,
Thank you very much for inviting me to Chris’s surprise birthday party. I am very happy you told me about this special plan.
I think Chris will really enjoy the surprise party because he likes spending time with friends and family. He always says birthdays are more special when everyone is together. Also, he does not expect this party, so I believe he will feel very excited and surprised. He likes surprises and fun events, so this will make him very happy.
Unfortunately, I am very sorry that I cannot attend the party. On that weekend I already have an important work commitment that I cannot change. I tried to move it, but it is not possible. I feel very disappointed because I really wanted to celebrate with him.
However, I am planning to see Chris the week after his birthday. I will invite him to dinner at his favourite restaurant and give him a small gift. I hope we can spend some nice time together and celebrate in another way.
Thank you again for inviting me. I hope the party will be wonderful and successful.
Kind regards,
Sandy