This chapter of the guide to Dragon Ball Z: Kakarot has a walkthrough for Reunion with Suno side quest.
Time frame: From Majin Buu Reborn - Episode 8: Finale to No time limit
Reward: 241,638 EXP, D Medal, Gold Compass, Fancy Necklace
Where to start: North Mountains Area, as Goku.
To start this mission, you have to go the North Mountains Area. Suno is waiting for you there - she will give you a new substory.
The required items can be obtained from the places marked on the map or they can be purchased from a merchant. Hand the ingredients over to complete the mission.