How does changing the DNS effect my indexing with Google?

A shopping cart company is asking use to change our Godaddy NS information to thier Name Servers. Our current url structure for product pages is http://www.domain.com/shop/product html, this shopping cart company wants to change the url structure to http://www.domain.com/shop/subcategory/p鈥?/a> html.



If we are not happy with thier services, we want to change the dns back to our old server, but if google see's the new URL's and our old server still has the old URLS, will that report a 404 error and drop our rankings? becuase the new url structure does not exist on the old server?



And how long of a delay between changing NS information does it take?
How does changing the DNS effect my indexing with Google?
Delays of DNS servers tend to be 24-48 hours; it mainly depends on how often they go and check up on their data. Some will be faster, others slower. I have seen some take 3 days, others 3 minutes.