[Newbies] indexing into a collection

Greetings,

I have a OrderedCollection of DrivingDays.

an OrderedCollection(2016-01-02| quigley s| nil|18§ 2016-01-03| marianos fresh| nil|5§ 2016-01-04| fresh thyme| nil|5§ 2016-01-05| panda express| nil|3§ 2016-01-06| peets| nil|7§ 2016-01-07| starbucks| nil|3§)

I want to select aDrivingDay object from the list by date, update it by adding mileage and places visited and put it back into the list.

If I #select the OrderedCollection, I get a copy of the item, not the same one in the OrderedCollection.

How do I select an item in the list for update?

Sincerely,

Joe.