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When you select another chocolate you can change your quest. The video did not cover switching. Just click on a different chocolate on the right and you should see on the left where it asks for if you want to SWITCH. It says you will lose all progress, which in the case of the party booster is none, You don't ever want to do this quest.
@Jane_Van_Fleet mary's advise above is what you need to do. tip for chocolate box only select the colour candy quests or easy/hard/ nightmare level quests or collect colour bombs/stripped or wrapped candy quests. never do any lollipop / hand switch / fish or party booster quests if possible. you can scroll back and do any quest on the easiest of levels available