Hi Guys,
I am trying to create a simple page header with a phone number in the top left (left aligned) & an email in the top right (right aligned) (desktop). When the screen is resized for mobile, I would like the two span6's I have to turn into span12's so that the phone number and email are a) stacked on top of each other and b) centered.

Any suggestions? I know this is much easier in later versions of bootstrap, but upgrading at this time is not an option.

Thank you.