What kind of action by the pilgrims, if abandoned, requires paying a penalty (دم)?

What kind of action by the pilgrims, if abandoned, requires paying a penalty (دم)?

حجاج کی طرف سے کس قسم کا عمل، اگر ترک کر دیا جائے تو جرمانہ ادا کرنا ہوگا؟
Explanation

 Suppose a pilgrim abandons a Wajib (mandatory) action during Hajj or Umrah.

In that case, it requires a penalty (دم) to be paid, which usually involves sacrificing an animal or other compensatory actions.