at sb’ s discretion (=according to sb’ s judgment or decision) Shops will exchange unwanted goods entirely at their discretion. 按照某人的判断；由某人斟酌决定

exercise/use discretion Teachers must be allowed to exercise their own discretion in choosing suitable classroom materials. 必须允许教师自主选择适合的课堂材料。

The investigation will be carried out with the utmost discretion. 调查将极其谨慎地进行。