Recolonizing a chapter

[AnchorAlumna]

As for how long it takes, it could be anywhere from a year to 4, 5, 10 years. It depends on the campus's need for more sororities.
Your best bet is still to talk to your school's Greek life office.
After that, you could also call the sorority's national/international headquarters and talk to someone there, but don't be surprised if they decline to talk to you.
Another tack would be to form a local sorority...maybe with the hopes of one day affiliating with a national. That's still going to take a long time to set up, and even longer - years, possibly - to affiliate with a national.
Again, talk to your Greek life office to see what the needs are and how you'd go about creating a new organization.