If you need anything, I am at your service.

您要是需要什么，请尽管吩咐。

《牛津词典》

I am writing to tell you that we were quite disappointed with your service. We had booked a table, but when we went there at the time as arranged, only to be told there were no seats available.

我想写信告诉你，我们对你的服务非常失望。 我们已经预订了一张桌子，但是当我们按预定的时间去那里的时候，却被告知没有座位了。

youdao

"Here I am, at your service," answered the carpenter, raising himself on to his knees.

“我在这里，乐意效劳。”木匠跪着回答说。

youdao

"This is a symbol, it is a sign washing your feet means I am at your service, " Francis told the youngsters.

NPR: Pope Washes Feet Of Young Detainees In Ritual

On 29 April, the wedding service begins at 11 am.

BBC: Going to London for the royal wedding

At 11:30 AM, the Vice President will host an event to launch a new Public Service Announcement (PSA) at the White House.

WHITEHOUSE: Vice President's Schedule