"互相交换"用英语可以说作"exchange with each other"或"mutually exchange"。
"exchange"的意思是"交换"，而"with each other"是"互相"的意思。"mutually"是"相互"的意思，所以"mutually exchange"也可以表达"互相交换"的意思。
例句：
"We decided to exchange phone numbers with each other so we could stay in touch." (我们决定互相交换电话号码，以便我们能保持联系。)
"They mutually exchanged gifts at the end of their visit." (他们在访问结束时相互交换礼物。)