Upgrading

I have booked flight to Orlando in August travelling PE. I paid full fare for my ticket and used my points to get a companion flight for my Husband. My husband then used his points to buy two tickets for my son and mother using miles and money, we then paid full fare for my youngest son. If I wanted to upgrade one leg of the journey to UC, will I be able to do this on the companion and the two reduced fare tickets. Any help would be greatly appreciated.[?]