MEK1 - BDC , ABAP error

I want to clear the default values displayed on the screen. When i call MEK1 for the very first record on BDC run, it runs properly and when the run reaches the second record , then the values of the first record are defaulted in the system.

For eg , the field condition type (char 4) in the very first screen, is filled up with the old records value , say ZXXX and now the second record has to put the value ZYYY. Now im not able to place ZYYY , i.e im not able to send any values to this field from second record onwards and only ZXXX is maintained throughout the run. I know that the solution would be simple and straight forward but not able to guess. Appreciate ur advice.

Thanks,

RB