[Typo3] Display a news fields after requestupdate

[Richard]

Hi :)
Extension dev
Backend section  tca.php
I know the requestupdate ask the user to save/update the form due to
changing the element.

Scenario:
When I create a New record
1- the user fill in the field1
2-  The BE ask the user to save/update the form.
3- 3 new fields appaears in the form.
How to display the new field after the requestupdate?

tank's Richard :)