I posted a request for change of denominations and Numista Robot responded with
Numista Robot
Hello 🤖
It is not possible to change username on Numista.
See https://en.numista.com/help/can-i-change-my-username-187.html
Please note that this is an automatic message. Feel free to ignore if it is not relevant.
This message could be filtered based on the type of request. Do not display the message if the topic is marked as a request about an object page or database entity (issuer, currency or denomination, ruling authority…).