Marrying divorced first wife again

Look into def. of Family in applicable pension rules.

If the original asker of this question is the husband then Ramesh Singh answer may work. But more importantly for my own curiosity, why not a fresh 20 year old? Just wait a year or two as a single man and meet new people. After that decide if you still want the old first wife to be the new wife. Or if she still wants you. If the 1st wife (who is now going to be the 3rd wife) is the asker, get the official marriage certificate and change your passport as wife of so and so. Then submit to pension office.