1. Ensure both buds are inside the charging case with the lid closed. Take both buds out from the case. 
2. Select "Vervebuds 500" from the smartphone Bluetooth menu. 
3. Switch off the right bud by either holding MFB for 2 seconds or by putting the right bud into the case with lid closed. 
4. Put the left bud into pairing mode by holding it for 5 seconds. 
5. Select "Vervebuds 500(L)"