ti identify discrepancies in internal table data

Hi all,

I do have data in internal table like this...

PODTD Instl Instl.type Premise ContractAccount

100 I1 ELED P1 C1

100 I2 ELES P1 C1

101 I3 ELED P2 C2

102 I4 ELES P2 C2.

I want to delete the records if PODTD are same for the same contract account.

only want to display different PODTD exist for the same contract in the report.

How can i do this check in internal tables? Please give me yours valuable guidance>......

Thanks.<b></b>