In family-based categories, you may apply to change your status in the United States if you were lawfully admitted into the US as a nonimmigrant, have not committed any act that would make you ineligible to receive an immigration benefit, and there is no other factor that requires you to depart the United States prior to making a reentry based on a different classification. The change of status application needs to be filed before the expiration date on your I-94.
In employment-based categories, your prospective employer needs to file a Form I-129 petition before your I-94 expires. The Form I-129 needs to establish that you will be performing the type of work covered by the new nonimmigrant classification for the petitioner and that you personally meet the requirements for changing your status. You cannot begin work in the new classification until USCIS approves the change of status.
Please be aware that not all nonimmigrant visa categories are eligible for change of status. To learn more if you are eligible to change status contact our office.