What accounts for "Material alteration" in cheque issued in the case of which banker rejects the payment for it?

Changing the amount of the check, changing the name of the payee (the person to whom the check is given), or making other changes on the check, such as to the date or to the name of the drawee (the person from whose bank account the check is withdrawing funds) or paying bank can be considered as material alteration.

Material Alteration:

Alteration in an instrument so as to alter the character of an instrument for example when date, amount, name of the payee are altered or making a cheque payable to bearer from an order one or opening the crossing on a cheque

AGREE WITH MR VENKITARAMAN ANSWER 

Agreed with Mir and Venkitaraman.

Alteration in the name of the payee, amount and date are considered as material alteration, for which a banker can reject the payment.