"Field 2" cannot be greater than "Field 1", how to implement it in BP?

Question

Bitrix24

Guys ...
Let's say there are 2 fields (money):
-Field 1
-Field 2

How to register in the BP that "Field 2" could not be more than "Field 1"?
And let's say if suddenly the number in "Field 2" is greater than in "Field 1", then after saving, reset it to 0.

Answer 1

And let's say if suddenly the number in "Field 2" is greater than in "Field 1", then after saving, reset it to 0.

For this option, it is as if you can write a Deals process that will be triggered when deals are changed.
It should contain a condition check construct, where:
1. If Field 2 > Field 1, then "Change document": Field 2 = 0
2. Otherwise - Do nothing.