I'm sorry I didn't attend the reunion.

It's a pity that I didn't attend the class reunion. I miss you very much.

According to Baidu Library, if you miss the class reunion, you can send a sincere message or email to those who attend the class reunion to express your regret and nostalgia. Here are some sentences that can be used to express regret:

1. It's a pity that I didn't attend the class reunion. I miss you very much.

I'm very sorry that I didn't attend the class reunion. I hope to see you again in the future.

I'm sorry I missed the party, but I hope we can keep in touch in other ways.

I'm very sorry that I didn't attend the class reunion, but I hope you all have a good time.

I'm sorry I didn't attend the class reunion, but I look forward to meeting you next time. No matter which expression you choose, you should sincerely express your feelings and let the students know that you care about their party and hope to keep in touch with them.