The decision in this regard was taken at a meeting of the Left Democratic Front (LDF) here today.
The swearing-in of Chandy will be held at 4 PM here tomorrow, NCP Kerala unit President Uzhavoor Vijayan said.
The three-time MLA is a prominent businessman and is said to the richest member of the state assembly with schools and resorts.
Saseendran had resigned on March 26 after a purported audio clip of him speaking in 'sexual undertones' to a woman emerged.
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