How to change the display of a variable on the screen or delay execution?

Question

PHP

Hello guys, please tell me how you can change the output of a variable on the screen,
for example:

$first = "Привет";
echo $first;

//Какой то код...

$first = "пока";

It is necessary that the second value of the variable be displayed on the screen, is this even possible?
If not, is there any way to delay code execution?

Answer 1

Echo after second variable declaration