Entity Framework 4 Delete Object from entity collection

I have a "Request" Entity with an 1..* relationship to the "RequestProperty" Entity. So there's a collection of RequestProperty objects in "Request". When I update a "Request" I want to delete all items in the RequestProperty EntityCollection and add the new items from the incoming domain object. When I iterate over the Request.Properties collection and call a remove or a DeleteObject on the item, the enumeration fails because the collection has been modified.

As of now I'm doing this:

while (true)
{
    if (newRequest.Properties.Count > 0)
        context.RequestPropertySet.DeleteObject(newRequest.Properties.First());
    else
        break;
}

Since this is not really "cool" I thought there must be another way to empty a collection of a relationship. Thank you for your thoughts.