হাওড়া - বর্দ্ধমান কর্ড লাইনে যান, 130 কিমি বেগে ট্রেন যাওয়াও কালবৈশাখী ঝড়ের থেকে ভয়ঙ্কর! - Jishnu Thakur

Actually on PRS tickets one can do this at counters (before chart preparation) by paying only clerical charges (I did it from 2ac to 1ac in KSK by paying I guess 50-55 Rs) but still not available in e-tickets. For that you have to cancel & rebook which results in loss of 200 rs (+ convenience charges twice). It should be provided on IRCTC too (& that too till 2nd chart preparation, i.e. 30 mins before dep)

---