Can I swap the ends of a retractable extension cord?
It is not directional, but its position in the circuit does matter.

Most likely you are not looking at a circuit breaker, but a GFCI.  These turn off the power if there is power coming out the hot wire but not returning through neutral.  Which is what happens if someone touches one of the wires and a metal pipe.  It is there to help prevent people from getting shocked, especially in wet environments.

If you swap the ends, it will still protect devices plugged into the cord, but probably won't be protecting its own wire anymore, which could be dangerous.

If it is just a GFCI plugging it into a GFCI receptacle would be fine &mdash; the receptacle will provide the same protection.  The only downside is if it does trip, you will have to check both GFCIs to see which one needs to be reset.

If it is actually a circuit breaker, it will no longer be protecting its own wire, since if there was a  short in the wire the current doesn't flow through the circuit breaker.