回複：I94卡問題

１。入境時是J1,　i94卡上寫的expiration date: D/S. 去年八月轉成H1,問題：是否需要更換新的I94卡？
-- In my case, my H1 approval notice came with a new I94.

２。入境是H1,I94給的有效時間與H1一致 (eg. expiration date: 8/31/2004)， 三年後H1 延期, 舊的I94是否已經失效？是否需要更換新的I94卡？
---When you renew your status, a new I94 Card should be attached to the approval notice.

３。如何更換I94卡?
--- Once you leave U.S, you turn in your current I94. When you come back, you will be issued a new one.
Or as I said above, new I94 should come with the status renewal approval.