Place the earbuds back into the charging case and keep the case open, tap and hold the button at the back of the case for 10 seconds until both the earbuds' LED lights flash red 3 times. This will clear the pairing information and restart automatically.
You can also click the following link which is showing how to reset the headphones: https://youtu.be/EmMsAFwg0B0
If you have additional questions, please contact us at Service@soundcore.com for further assistance.