Q:

Converting IFs to LINQ

Could someone help me converting this to LINQ?  Any help/tips appreciated... 
IList<DestinationSummary> list =
    _invoiceReportDao.InvoiceDestinationSummary(filter);

IList<DestinationSummary> updatedList =
    new List<DestinationSummary>();

foreach (DestinationSummary item in list)
{
    if (item.ChargeCategoryDiscriminator == "INT")
        item.ChargeCategoryDiscriminator = "00%";

    if (item.ChargeCategoryDiscriminator == "UK")
        item.ChargeCategoryDiscriminator = "07%";

    updatedList.Add(item);
}

return updatedList;

A:

LINQ should not be used to modify objects.
Your code is fine as-is.
However, you can make it a little bit faster by initializing the new list form the old one:
IList<DestinationSummary> list = _invoiceReportDao.InvoiceDestinationSummary(filter);
IList<DestinationSummary> updatedList = new List<DestinationSummary>(list);

foreach (DestinationSummary item in updatedList)
{
    if (item.ChargeCategoryDiscriminator == "INT")
        item.ChargeCategoryDiscriminator = "00%";

    if (item.ChargeCategoryDiscriminator == "UK")
        item.ChargeCategoryDiscriminator = "07%";
}

