I went to US as B1/B2 and changed my status to M-1. During my study I had a family problem and had need to came back to my country. I did all the process, informed the school and came back in 15 days. Is my B1/B2 still valid to visit US as traveler?
It should be still valid, unless subsequently cancelled by CBP at the airport where you will land.
It will be entirely up to the discretion of the CBP officer(s) whether to admit you on "B" visitor status or not. A still nominally valid visa on one's passport does NOT "guarantee" admission - merely the permission to board a US-bound flight - the rest is up to the CBP. If CBP will be convinced that you are coming for a "short visit", have enough funds to support yourself AND more likely than not will depart upon the conclusion of your "temporary" visit, then they could admit you into the country, otherwise not. Of course, your "past history" could loom large and influence CBP.
If my answer is the "BEST ANSWER" and/or "HELPFUL" please mark it accordingly. Fluent in 7 languages. Certified Specialist in U.S. Immigration & Nationality Law, The State Bar of California, Board Of Legal Specialization. 25 years of successful immigration law experience. The answer above is only general in nature and cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.
Years licensed, work experience, educationLegal community recognition
Peer endorsements, associations, awardsLegal thought leadership
Publications, speaking engagementsDiscipline