I was struggling with this on my iPhone today.  I have two browsers, Chrome and the built-in Safari.

My wife signed in to her GMail account Safari, and I signed in to my (Google-based) work email account in Chrome.  There doesn't appear to be any option to completely log out in either case.

![Initial screen][1]

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**When I tap on the "Sign in with a different account" link, I get this:**

![Second screen][2]

There's simply no option to sign out and sign in with another account.  Is this by design?


  [1]: https://i.sstatic.net/Jpd0N.png
  [2]: https://i.sstatic.net/IMACk.png