I helped a few guys reinstate their CFI last summer. I have a feeling this is going to be a common theme this year.

As a previous poster said, you have to take a checkride. Online software is only good for a renewal, not a reinstatement. You can take the ride with a DPE, so you don't have the headache of having to go to the FSDO, which usually means a 4hr oral and a 2hr ride. You can also take the ride based on any of the CFI ratings you previously held. Most guys I worked with took the CFII ride, one did the MEI. None did the CFIA b/c they didn't want to do chandelles, 8s on pylons or lazy 8s. I can't say I blame them. Take one ride, and it reinstates privileges for all CFI ratings.

It's self-endorsed. You don't need another CFI to sign you off, you just fill out and sign your own 8710.

My advice, if you haven't flown a Cessna or Cherokee in a while, do a flight with an experienced CFI who has been working with other CFI applicants. Not only will he keep you from flying final at 130kts and flaring at 50ft, but he'll also be able to familiarize you with the local airports, patterns and IAPs you're likely to visit on your check ride. If he's been working with CFI applicants, he'll likely know a good DPE to send you to as well as be able to give you the low-down on the ride before you go.