“委托代替”常见的英文表达可以是 “entrust someone to act as a substitute” 或者 “delegate the responsibility to a substitute”。
entrust someone to act as a substitute：强调将某项任务或职责托付给他人，让其作为替代者来执行。例如：He entrusted his colleague to act as a substitute at the important meeting.（他委托同事在重要会议上作为替代者出席。）
delegate the responsibility to a substitute：侧重于把责任下放给替代者。例如：The manager decided to delegate the responsibility to a substitute due to his urgent business trip.（由于有紧急出差任务，经理决定把责任下放给一位替代者。）