Hi! My company have locations in Mexico and USA, I work for my company in Mexico, I was assigned to work in a project in USA for 3-4 months, so the part of my company in USA send me all documents to process a TN Visa, including a document called TN Letter that is requested for this process; I attended the VISA interview I told them that my company in Mexico will continue paying my salary and I'll be living partially in USA and later when the project finished I'll return to Mexico (that was the original idea), the visa was approved. Now my USA company asked me if I can move to work in USA permanently, so they will give me a job offer for this if I accept.... my doubt is if I need to process again the TN Visa or if I can move to USA with the one that I have right now... sorry if this is confuse, let me know if you need more details to answer my question. Thanks!