RSS chief Mohan Bhagwat had last month held a dinner meeting with Advani and Swaraj to discuss this issue. Earlier, RSS General Secretary Suresh Bhaiyyaji Joshi had also met Advani and Swaraj separately to convince them on Modi.
It is not clear whether Advani has had a change of heart. However, the decision on when to hold the Parliamentary Board meeting is still hanging fire, the sources said.
Consensus on a suitable date when all members of BJP's highest decision-making body are present is being worked out.
While BJP and RSS top brass have indicated that any delay in announcing Modi as the PM candidate will not be good for the party, efforts are on for a unanimous decision after taking Advani, Swaraj and Joshi on board.
Modi's supporters in the BJP top brass are keen that the announcement be made before his birthday on September 17.