When does a Convert experiment status turn into "Complete" and what happens afterwards?
An experiment status will turn into "Complete" status when its statistical confidence has reached the configured percentage and has reached the configure minimums or maximums in its settings.
By default, this percentage is 97%. The default minimum days are 14. These settings can be changed during the experiment.
The default behavior after its completion is that the Original version will be served as default. This behavior can also be changed on the experiment settings.
For more information on experiment settings please read the following article.