Google appears to be rolling out a long awaited feature allowing Gmail users to change their email addresses while keeping their existing data. The option is quietly appearing on a Google support page, though it has not been formally announced and is not yet widely available in the United States. Under the plan, the old address becomes an alias that forwards mail to the new one. Users would be limited to one change every 12 months and only three total changes. Google has not said when the feature will fully launch.