Heads up: United has extended their no-fee-cancellation policy through the end of May. However, they have changed their refund policy on flights that they cancel FOUR times since March 7.

https://thepointsguy.com/news/united-schedule-change-policy/

Current policy on cancellations of international flights (Not sure what it is for domestic):

"And on Saturday, March 14, United changed the policy for the fourth time and made it much harder to get a refund. Now, the latest policy is that if your international travel is changed by six or more hours, you'll receive a travel credit to use within a year of your original ticket purchase date. If you want a refund, you need to wait until that full year elapses, and only then can you request a refund."