If an H-1B wants to change from another employer to employment at Ohio State, a new H-1B petition must be submitted to USCIS before the employee can start working at Ohio State. USCIS portability regulations allow the individual to start working at the new employer when the USCIS official receipt notice is received and it is on or after the requested start date of the H-1B petition.
The foreign national may need time for the physical move to Columbus. However, USCIS portability regulations do not allow a break in employment between the former and new employer. The employee must remain on the payroll with the current employer until the day the employee is placed on the Ohio State payroll, therefore maintaining continuous employment. Arrangements must be made with the former employer and Ohio State to accommodate the move. The portability petition takes 3-7 months.
See Step by Step for more details.