以便【yǐbiàn】

以便 opens the second clause and says what the action in the first clause is meant to make possible or easier. It belongs to writing and formal speech: notices, instructions, reports.

The clause after 以便 can have its own subject, different from the first one.

以便 comes second

为了 puts the purpose first, before the action. 以便 puts it after.

• × 以便我们联系您，请留下电话 → 请留下电话，以便我们联系您

Not for something to avoid

以便 leads to an outcome you want. To keep something from happening, use 以免.

• × 请早点出发，以便不迟到 → 请早点出发，以免迟到