Overridable calculated new request properties

We are working on a request form using the new Request Properties.

The requirement is like, when user click on a product, it appears a form and asks few fields to fill up.

One of those fields would be ‘User ID’.

The requirement is, when the form pops up, UserID filed should have a calculated CentralAccount name based on what we have in ‘Person-> CentralAccount’ template.

This filed will remain editable by the requester. In case the requester wants to set a different CentraAccount then he can override the system generated value and type his Own.

One Identity 9.2.1

API Portal.