If you report symptoms in the NHS COVID-19 app, the app will ask you to self-isolate and book a test. The self-isolation countdown timer will also start, from the date you said your symptoms started. The countdown is designed to help you understand how long you need to self-isolate for, in order to protect the general public from coronavirus (COVID-19).
If you have reported symptoms in error, and do not have coronavirus symptoms, you cannot cancel the self-isolation timer within the app. If you have started the countdown timer by mistake, we would advise that you just ignore it on this occasion. It will be on your phone only and no one else will be able to see it.