[Assigning a state loan to another for a price]

Answer: What is apparent from the question is that the loan mentioned is not actually a loan, rather it is assistance and a grant, because it involves waiving part of the loan and extending the term. The state grants it to some of its citizens either as a reward for their long service, or for their loyalty and success at work, or something similar.
On that basis, there is no harm in the beneficiary assigning his right to another for an amount of money.
Evidence: It is related that Amīr al-Muʾminīn Ali (Peace Be Upon Him) purchased a married slave-girl, and then bought her conjugal right (farjuhā) from her husband for five hundred dirhams—a sale of rights. This report supports the permissibility of selling rights.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2