I have a refundable/changeable ticket on AS F EWR-SEA Saturday night. I want to go home earlier. All the flights are FULL, even one-stops!

CO has 5 or 6 flights a day EWR-SEA. There are probably 7 CO flights I can try to standby on Friday and Saturday at the gate. But I don't yet have a CO ticket. What do I need to do to standby on these flights? Does my AS ticket have any value at the CO gate? Do I buy a changeable/refundable First Class ticket on CO from sometime next week, then ask the gate agent to let me standby? How does this all work?