I wonder if you could change the date of our appointment 

我想知道你是否能改一下见面的曰期。

I wonder if you could change the date of our appointment. 

我想知道你是否能改一下见面的曰期。

Isn't it available? OK. 

此日期不行是吗?好吧。

Please make an appointment with my secretary. 

请跟我秘书约定见面时间。

Please make an appointment with my secretary. 

请跟我秘书约定见面时间。

Thank you. I will. 

谢谢。我会的。