Can i change the return date on a award booking for free after travel starts?
 

I am thinking to book a UA award round trip and add a free one way (using the free stopover), ORD-PEK, PEK-ORD (stopver), ORD-MIA. I read it is free to "Change the departure to a date/time 21 days away or more". Can i change the return date on a award booking for free after travel starts? In other words, can I change the departure date from PEK for free after I arrive in PEK, but 21 days before depart from PEK? Also can I change the departure date from ORD to MIA for free? In that timeframe? (after coming back to ORD?)

Thanks.

In my experience, yes.

Yes, although you may have to call as the website doesn't always work so well for changing a half-used ticket in my experience. (You can of course try doing it online, and go online to check availability before calling).

I've had no problem doing this as a 1K. Of course you need to pick a day with award (saver presumably) availability.