Contract generally cannot be scratched or crossed. If any addition, deletion, and modification are needed, two parties should confirm the place needing any modification to show the seriousness.

写好的合同或协议一般不能涂改，如果必须增删修改，双方必须在改正的地方签字确认，以示郑重。

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On the appointed day, contact the customers to confirm whether they will come or not one hour in advance; if they cannot come on time, reschedule the time for them.

个小时与用户确认是否来访，如不能按时到访，为用户改约时间；

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"It was clearly involved in a serious incident, but we cannot confirm if there was an RPG (rocket-propelled grenade) attack, but shots were fired, " a British Foreign Office spokesman said.

CNN: Two guards hurt in Libya attack now in good condition

But caution: it may not be obvious to you at the time, but influencers cannot confirm whether their organization will actually buy, even if they give you the impression otherwise.

FORBES: Are You Making Something Usable? Part 4 -- But Is It Valuable?