conditional validation

Hello all,

I have a status and a date field. I want to setup a validation (conditional validation ?? http://www.yiiframework.com/doc-2.0/guide-input-validation.html#conditional-validation) so that

if the status value is changed, the date field value must be changed as well.

For example

Status: A

I change Status to B. If I dont change the date field value to new value, error should display and I should not able to save changes

Thank you