回复：回复：请教：怎样用美国驾照换加拿大驾照，同时还保留美国驾照

When you exchange your Canadian DL, you need to surrender your US DL. Your US DL will be returned to your State DMV. Even if you find ways to keep it, it is not valid any more. The card may not be physically returned, the information is returned.
You can change back to your US DL later, as long as it is within your US DL original valid period.