It should be Queued & shall come in to effect automatically on 29Apr2017 00.00hrs (Midnight of 28Apr2017).
You will require a Booster-pack which will last till the remaining days of the prevailing plan (validity till the expiry of the current plan).
Till date Jio has projected themselves differently compared to the regular prepaid module used by other companies wherein any prepaid recharge supercedes the existing plan/recharge. They have come up with queued recharges instead. They have introduced booster packs for prepaid users. Jio's prepaid Recharges give full 24 hrs cycle from the time of activation unlike other operators who forfeit plan at midnight irrespective of the time of activation.
Jio will observe it's users usage behavior after the commercial services start from April & may come up with some more plan variants by June for non prime customers as well.