Ankit, last year when Reliance did a rights issue, they issued partly-paid shares. This shares are partially paid compared to full issue price.
Reliance issued this shares at Rs. 1257, but only collected Rs. 314.25 upfront when shareholders made application for rights shares. For the remaining Rs. 942.75, company would collect the amount by making one or more subsequent calls.
So this is the first call of Rs. 314.25 for those partly-paid shares. Once this payment is collected, company will allot new partly-paid shares, paid-up to Rs. 628.5, the remaining 628.5 is scheduled to be collected in November 2021, after which the shareholders will receive fully-paid shares of Reliance.
One thing you need to keep in mind:
What will happen if I don’t make call payment?
The partly paid shares may be forfeited (the current Reliance PP shares you hold will be worthless and will not trade on exchanges as company will allot new partly-paid shares under different ISIN) if you fail to pay the call money. The company may also levy interest on the amount you owe.