It depends on what status you are changing to.
Guerra Saenz, PL--Immigration Attorneys (954) 434-5800. This answer is of a general nature and should not be relied upon as final, nor is it intended as legal advice.
You should meet with an experienced immigration law attorney to discuss your options. You need to identify what status you will be seeking in order to obtain information about the forms and documents needed for your case. Your tags for this question indicate both B-1 visa and Visa extension. Each option would require different recommendations.
The answer provided does not create an attorney-client relationship and is only based on the information submitted in the question. If other information were submitted, it could result in a different answer. Consult with an experienced immigration law attorney for legal advice.