Last month, United Airlines rolled out its “CleanPlus” program. It included a number of initiatives aimed at improving health and safety, developed in partnership with Clorox and Cleveland Clinic. Now, the carrier is expanding its efforts, requiring passengers to acknowledge that they’re healthy and willing to comply with airline policies during the check-in process.All United passengers — including standby travelers — are now required to complete a health acknowledgement when they check in for their flight, similar to a policy currently in place with Frontier.Sign up for the free daily TPG newsletter for more airline newsPhoto courtesy of United Airlines.In order to be deemed safe to travel on a United aircraft, customers will need to acknowledge the following:You must wear a face covering while on board for the safety of everyone.You have not been diagnosed with COVID-19 in the last 21 days.You have assessed yourself for COVID-19-related symptoms, and haveexperienced none of the following in the last 14 days:Known temperature of 38 C/100.4 F or higherCough (excludes symptoms from a pre-existing condition)Shortness of breath/difficulty breathing (excludes symptomsfrom a pre-existing condition)ChillsMuscle painSore throatRecent loss of taste or smellYou have not been denied boarding by another airline due to a medical screening for a communicable disease in the last 14 days.You have not had close contact with someone who tested positive for COVID-19 in the last 14 days.More: How far can airborne covid germs really spread on a plane?Anyone who doesn’t meet the requirements outlined above will be asked to reschedule their trip, which most travelers can currently do on their own, thanks to the airline’s no-change-fee policy.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.United is also giving passengers the option to make free changes on flights that end up being more full than expected — passengers can move to a flight with more space if their original flight has checked in above 70% of full capacity.More: American, Delta and United plan to fly these long-haul international routes in June