The "change of address" feature in GWT only work with root domain, how can I use it for sub-domain?

Selected answers from the Dumb SEO Questions G+ community.

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  Alex G: We moved a subdomain url address to another subdomain is 301-redirecting to
  
  The question is how I go about the change in the webmaster tools? The "change of address" feature only work with root domains and I cannot use it for subdomains. What is the proper way to notify Google crawlers about my subdomain change?
  
  Thanks!
  -Alex G
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  Phillip Marquez: Are you doing 1:1 301 redirects (page for page)?  ;If the site subdomain isn't too big, I would do 1:1 redirects and leave it alone for at least a few weeks (at least 2-3 weeks, but preferably longer).  ;
  
  A 301 tells crawlers that a page has permanently moved and indices should update organically over time.
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  Alex G: Yep, I am doing 1:1 301 redirects. Should I change all the urls to the new subdomain even though my webmaster tools account is still registered with the old subdomain? ;
  
  Also I see both subdomains show up in search results. What should I do about it?
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  Phillip Marquez: I would follow the guidelines from Webmaster Tools (), minus the bits about using the change of address tool of course.  ;It might take a bit of time before you are reasonably sure that 1) the old is no longer in SERP and 2) traffic no longer goes through your 301s though.
  
  If you're already routing your traffic to the new subdomain, then yes, you should start focusing on the new subdomain -- make sure your WMT has the domain validated, analytics is setup, etc.
  
  In a nutshell, make sure your foundation is set -- robots.txt, sitemap, 404 strategy, etc. If you're not already using canonical tags, then you should update the NEW pages with self referencing canonicals (this will reinforce the SERP for the new page).  ;If you have crawling sofware, feed it your old sitemap and make sure all your 301s are working (obviously you'll need a crawler that takes an XML file vs an actual crawl since each page will redirect).
  
  In GWT I would keep an eye on crawl errors report to ensure everything looks good on the new site.  ;Continue to monitor the old subdomain as something will popup sooner or later that you hadn't thought of before hand.  ;Monitor your SERP for the old domain.  ;If you aren't already aware, you can use "site:" (use your own domains of course :P) to see what pages are in the index (you can also use "info:" for a list of other useful searches).
  
  Good luck!
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  Alex G: Should I create a new profile in WMT for the new subdomain since I cannot update the old one? If I create a new profile I can add a new subdomain and the new sitemap. However will I have any problems by having 2 profiles in WMT, essentially for the same site?
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  Tony McCreath: You should register both subdomains in GWT and then you should be able to do the change of address between them.
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  Phillip Marquez: + ;you cannot use the CoA tool for subdomains -- if you have multiple subdomains, go to the tool and try it, subdomains are not listed in the drop down.
  
  + ;- I'm not sure I'm following your question about WMT.  ;You should be able to add the new subdomain to your existing Google Account (the old subdomain will become  ;(or, it sounds like, already is) unavailable in WMT, which is fine.  ;If you've lost access in WMT for the old site, but you still own the hosting/domain for it -- you can revalidate it in WMT with the HTML file option (obviously don't redirect on this file, haha) and access will return if you need/want it.
  
  Either way, yes, you want to have the new subdomain vaildated in WMT for all the same reasons you needed the old subdomain validated -- sitemap submission, various reports, etc.  ;You should not have to create a new account/profile, although you certainly can if it's easier for you.
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  Tony McCreath: + ;your right. just www subdomains show. This may be related to the recent issue that https websites don't show either. ;Apart from on my account!
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  Alex G: Thanks guys. Now if I do verify and setup both subdomains in WMT will I see both subdomains showing up in search results as they do now? (I am pretty sure with 301 redirects the old URLs should go away from SERPs, right? Is there anything I can do to expedite the process?)
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  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 01:00:37 into the YouTube video: +
  
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