请教：1。现持H4 签证，到明年九月过期。 如果无任何变化， 明年九月需续签？ 到Border 就行？
-Either is way is OK if you ar ea Canadian citizen.
2。明年一月有一临时工， 需要去Border 办TN visa, 是否拿到TN， H4 就自动无效了？
-Yes. You only can have one status at one time.
3。 主申请在办理PERM，若几个月后批准， 是否只有 当时拿 H4 才可以file EAD？，
-If you mean you are qualified for H-4 EAD, then you have to have H-4 status to apply for it.
拿着TN可否file EAD？
-No for H-4 EAD.
4。 如果上述任何一个成立， 是否需要申请在TN 和 H4 间转换 ， 如何办理？
-You can go ot the border to get a new status (H-4 or TN), or file I-539 to change status within US which may take 3 months to get the new status within US.
