Deleting all sheets except one

[Nirmal Singh]

I have a workbook in which I need to delete all sheets except one
called "SummaryReport". I have tried using the following code

For z = 1 To xlBook.Worksheets.Count
If xlBook.Worksheets(z).Name <> "SummaryReport" Then
xlBook.Worksheets(z).Delete
Next z

This is falling over (I presume because the count changes as sheets
are deleted). How can I do this?

Nirmal