Veteran leader Mallikarjun Kharge will formally take over as Congress president on Wednesday after he is handed over the certificate of election at a function here. Hectic preparations were underway at the Congress headquarters on Tuesday for the ceremony where outgoing president Sonia Gandhi will hand over the reins to Kharge, the first non-Gandhi to head the party in 24 years. Kharge defeated Thiruvananthapuram MP Shashi Tharoor in a direct contest for the top post in the grand old party after the Gandhis opted out of the race.