1. SIN-SFO x 2 (UA 28)
2. 3 Sept
3. Booked 4 August
4. W
5. Y --> C
6. Cleared at booking

This itinerary was purchased two months ago. I saw P9, PN2 and PZ2 this morning and decided to upfare from K to W. After I cleared the upgrades, it became P7, PN0 and PZ0.