NEW YORK (Reuters) - U.S. President Joe Biden said on Monday that he is open to negotiating the eligibility requirements of his proposed $1,4000 COVID stimulus check, a nod to lawmakers who have said they should be more targeted to lower-incomes. The previous round of stimulus checks, including the $600-per-person check approved in December, was generally limited to individuals earning less than $75,000 a year and married couples earning less than $150,000.