I'm a little confused with method 1 from the document. If I understand it correctly the Method 1 can be done
"Adding the Replacement MX to the Same Network" or "Adding a Second MX to Form a Warm Spare Configuration".
I understand for both you have to remove the old MX prior to adding the new one. How can you add a warm spare if you have removed the old MX? Can I assume there will be no downtime when I add the new as a warm spare and than remove the old MX? I just want o make sure I understand it correctly.