How to rename value in a List without creating a new one?

I have a list of strings List<string> blobsToCopy

var newList = blobsToCopy.Select(GetDiskNameWithoutFolder);
private static string GetDiskNameWithoutFolder(string path) {...}

How to change all values in the blobsToCopy without creating a new IEnumerable<string>?

You don't use LINQ, just use a simple for loop and replace each item with your modified item.

for (var i = 0; i < blobsToCopy.Count; i++)
{
     blobsToCopy[i] = GetDiskNameWithoutFolder(blobsToCopy[i]);
}

Unless I'm missing something obvious, what's wrong with a good old-fashion for loop?

for(var i=0; i < blobsToCopy.Count;i++)
{
    // do whatever....
}