Finalization of the site on the framework yii2

There is a site with elements of an online store ksytal.com, written on the yii2 framework. I am interested in the possibility of making the following improvement in it:

1. If an individual chooses SDEK and makes a large order (conditionally for 30 thousand. rubles) then the delivery becomes free (i.e. the column of the amount of delivery disappears), while everything else remains as it was (SDEK widget, etc.)

2. If an individual makes the same large order (conditionally for 30 thousand. rubles) through SDEK, the site in the basket calculates a discount, which we ourselves can change (if necessary later)
(a) Percentage
b) in rubles

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