Multiple Labor rates

Our operators have set rate per employee based on an average hourly
rate for the department they are assigned to. Our Tooling Machinist
charge out at a higher rate then or Turning Machinist, we use our
Tooling Machinists to do production work from time to time and when
they log into a job we would like to charge their time out at the lower
rate of the Turning Machinist.

We do not use the Vantage payroll module and all costs are charged to
the job.

How can we switch the Tooling Machinist rate to the lower Turning
Machinist rate when the Tooling machinist is performing turning work?

Is there a way to have the operator over ride their rate based on the
labor expense codes through the shop floor module?