Trip delay impact when air tickets bought with miles on United?

[CK57]

What happens if your tickets are bought with air miles on United and your trip home is delayed due to Covid isolation?  Will you be able to change flights without a change fee and keep same class of ticket?  I have not found any flight insurance or trip insurance that covers airfare bought with miles?   Thanks

 

[6rugrats]

https://www.united.com/ual/en/us/fly/travel/change-fee.html