Need formula to solve the problem

Hi,

I have a data as mentioned in IMAGE.

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The excel sheet is showing data for the person who entered into the city and left the city and he has shown the type of ID proof at any point of time during his visit to city. But the person who collect the data forgot to fill up the date ID Checked. But other person has data only the date ID checked and type of proof.

I want to apply formula which check whether the unknown person is the same as the person whose id was checked by comparing his duration of visit and type of ID proof. e.g. Garry has visited Ohio city between 19-Aug-2009 to 02-Sep-2009 and shown ID proof '1'. And has a data that one Unknown person has shown ID card '1' on 02-Sep-2009. So, I can predict that Garry has shown card on 02-Sep-2009.

Please help me for the formula which can check the bulk of data.

Thanks,
Cbtech