How should I choose or change a Virgin Atlantic seat when the published advance-fee rule excludes US bookings?

What this answer depends on

• Virgin Atlantic same-cabin seat selection and the public page’s US-booking exception; exact US fare entitlement is not inferred
• The page gives a US-booking exception but does not establish every American booking’s exact price from that footnote alone. Confirm the fare and displayed selection in My Booking. Record what the airline actually offers instead of importing a non-US statement or assuming the exception means every seat is free.
• Virgin describes same-cabin seat changes before check-in. Moving to a different cabin is an upgrade, not simply another seat selection. Preferred seats can exist toward the front of Economy or Premium; the word “Preferred” alone therefore does not identify a cabin upgrade.
• The published rule allows a paid Preferred customer to move to another available Preferred seat in the same cabin without another Preferred charge. It is not a promise that any chosen number remains available or that moving to another category has the same financial result.
• Virgin’s general advance-selection fee wording explicitly excludes bookings from the US.
• Virgin allows seat changes before check-in within the same cabin; a different cabin is a separate paid upgrade.
• A customer who paid for Preferred may move to another available Preferred seat in the same cabin without another Preferred charge.
• Virgin describes Preferred seats toward the front of Economy or Premium.