Saudi Arabia had known that it can employ Mansour Hadi in Yemen as the former president before his resignation and make it as a legitimate presidential recognized internationally for the Security Council.
Saudi Arabia was known that Hadi can employ this legitimacy to impose Riyadh as place for dialogue and its reference.
Saudi Arabia was known in advance that the success of the dialogue and imposition its trusteeship on Yemen again, depend on the acceptance of the Houthis to response dialogue in Riyadh with its own conditions, so this is impossible.
Saudi Arabia was known that the Houthis refusing for dialogue in Riyadh will weaken Hadi's capacity just in re-use of recognized legal status in the Security Council to request the intervention of the Peninsula Gulf governmental forces in this conflict, which is developed and progressed in Yemen.
Saudi Arabia knew that this provocation equivalent of surrender, and the intervention equivalent occupation.
This will lead to launch an open military confrontation in Yemen.
The Houthis are progressing towards Aden and Bab Al-Mandeb.
Saudi Arabia's ability is confined, so it accepts to change the place of dialogue for Doha instead of Al-Riyadh and without preconditions.