在英语中，"和朋友相约"可以用以下几种表达方式来表示：

Make plans with a friend: 与朋友制定计划
例句：I'm going to make plans with my friend to go to the beach this weekend. 我打算和朋友计划这个周末去海滩。

Set a date with a friend: 和朋友约定时间
例句：I'm going to set a date with my friend to meet at the park on Saturday. 我要和朋友约定在周六在公园见面。

Make an appointment with a friend: 和朋友约定会面
例句：I'm going to make an appointment with my friend to have lunch together on Wednesday. 我要和朋友约定在周三一起吃午饭。

Meet up with a friend: 和朋友见面
例句：I'm going to meet up with my friend at the coffee shop after work. 我要在下班后和朋友在咖啡店见面。

这些表达方式都可以用来表示"和朋友相约"的意思，但有些稍有不同。"Make plans with"指的是制定具体的计划，"set a date with"指的是约定具体的时间，"make an appointment with"指的是约定具体的会面，"meet up with"指的是见面。