He is the host at the reunion.
他是聚会的主人。
Her description of the meeting is an exact reproduction of the reunion.
她对会面的描述是这次团聚的真实再现。
Thanks invitation however regret unable join owing business pressure hoping reunion before christmas best regard.
谢谢邀请,很抱歉,由于商务繁忙不能前往。希望在圣诞节前能得到一叙。祝好。