Registration of physical person as individual entrepreneur doesn't create a legal succession. Therefore there are no bases to change the contract.
The explanation concerns a case when the customer signed the contract with physical person which then received the status of the individual entrepreneur. According to department, such contractor has the right to continue to fulfill contract obligations as physical person. It isn't necessary to make changes to the contract.
We recommend to customers to adhere to a line item of the Ministry of Economic Development especially as the Law N 44-FZ doesn't provide the bases of change of the contract in this situation.
Let's remind if the state customer changes terms of the contract in the absence of the bases for this purpose in the legislation on contractual system, it can be "fined" 200 thousand rubles, and the official - 20 thousand rubles.
Document: Letter of the Ministry of Economic Development of the Russian Federation of 13.10.2016 N D28i-2764