Joint development agreement and gpa

Hello,

 I am purchasing a plot from a developer who developed the land with joint development agreement (JDA) with the land owner. And land owner as given GPA to the developer and the GPA is registered.

Developer and land owner have share the property in 60:40 ratio.

Question:

The plot i am buying falls in the developer share. Can developer execute the sale deed or do we need the owner to execute the sale deed ?

Guru