Rabri Devi, the wife of RJD chief Lalu Prasad, is expected to meet the investigating officer (IO) of the money laundering case at the ED zonal office in Bihar's capital and record her statement.
Lalu Prasad was the railway minister in the UPA-I government.
She has skipped appearing before the agency at least six times in the past and it is understood that the central probe agency allowed her request to be questioned in Patna and not in Delhi, where the criminal case has been registered.
The ED has earlier questioned Rabri Devi's son Tejashwi Yadav, the former deputy chief minister of Bihar, twice in this case.
In July, the agency registered a case against Lalu Prasad, his family members and others under the provisions of the Prevention of Money Laundering Act (PMLA).
Just before this, the Central Bureau of Investigation (CBI) registered a criminal first information report and conducted multiple searches on the properties of Lalu Prasad and others.
The CBI FIR alleged that Lalu Prasad, during his tenure as the railway minister in the UPA-I, handed over the maintenance of two Indian Railway Catering and Tourism Corporation hotels to a company in 2004 after receiving a bribe in the form of a prime land in Patna through a 'benami' company owned by Sarla Gupta, wife of Prem Chand Gupta, a former Union minister.
The ED registered the criminal case against his family members and others under the PMLA, based on this CBI FIR.
The CBI has already recorded the statements of Tejashwi and Lalu Prasad in this case.
The ED is investigating the alleged "proceeds of crime" generated by the accused, purportedly through shell companies, according to the officials.
Others named in the CBI FIR include Vijay Kochhar, Vinay Kochhar (both directors of Sujata Hotels), Delight Marketing company, now known as Lara Projects, and the then IRCTC managing director P K Goel.
The CBI FIR was registered on July 5 in connection with favours allegedly extended to Sujata Hotels in awarding a contract for the upkeep of the hotels in Ranchi and Puri and receiving premium land as "quid pro quo".