Eingyi not ascneding flame

So I saw Eingyi, and talked to him, got his spells via the egg head, But he refuses to ascend my +15 pyromancy flame to the divine level.

He gave me a new flame, whcih i am in the process of getting up to +15.

How do i get him to ascend my flame??

Only Quelana can Ascend your Flame to the super powerful version, if you don't know where she is she is sitting on the ground next to one of the pillars in blight town. I believe there is a Large titanite Shard corpse near to her, basically you can see Q's domain from where she is. it's not entirely known when she appears, but it is related to a +10 flame, and killing Quelag.