Seoul, March 12 : US President Joe Biden has formally requested South Korean counterpart Yoon Suk Yeol to chair a plenary session of the second Summit for Democracy, according to Yoon's office on Sunday. It made public a scanned image of Biden's recent letter to Yoon asking him to "lead one of the five plenary sessions" on March 29, Yonhap News Agency reported. The summit is scheduled to be held on March 29-30, co-hosted by the US, South Korea, Costa Rica, the Netherlands and Zambia. It is to assemble world leaders in a virtual, plenary format. In the letter, Biden said Yoon's "close and tireless cooperation has helped ensure that this Summit will be a success." Co-hosting the event "reinforces the truth that democracy is both a shared aspiration and a shared responsibility -- one that we all must uphold," Biden added. /IANS