If you must know how to resell SEO, it helps to connect with others whom you know who have taken on reselling seo themselves. They can at least give you a framework so you comprehend the overall nature of SEO. Then you can decide where to resell it.
If you desire to know how to resell SEO, also browse online articles to get a stronger sense of how the back end of things work. While this knowledge is not mandatory to resell SEO, it certainly helps, if only to broaden your knowledge of something that you will eventually be selling yourself.
If you absolutely need to know how to resell SEO now, learn whether an SEO expert will be speaking somewhere anytime soon. You can listen in on the seminar and jump further ahead in the knowledge spectrum of the SEO world. Plus, you can speak with the lecturer afterwards.