Interface that is implemented to multiple classes (different types of objects)

Method in class1:

public Employee CreateEmployee(EmployeeCreateModel1 model) { .... }

public Employee CreateEmployee(EmployeeCreateModel1 model) { .... }

Method in class2:

public Employee CreateEmployee(EmployeeCreateModel2 model) { .... }

public Employee CreateEmployee(EmployeeCreateModel2 model) { .... }

How could I create interface that would be used for both of them..

public interface EmployeeService {
  Employee CreateEmployee(??? createmodel);
}

public interface EmployeeService {
  Employee CreateEmployee(??? createmodel);
}

Any idea/advice?