In what condition the opposition may declare a vote of no confidence against PM in national assembly of Pakistan?

In what condition the opposition may declare a vote of no confidence against PM in national assembly of Pakistan?

اپوزیشن کس حالت میں پاکستان کی قومی اسمبلی میں وزیراعظم کے خلاف عدم اعتماد کا ووٹ دینے کا اعلان کر سکتی ہے؟
Explanation

Currently the National Assembly can not be dissolved by the President of Pakistan; it is dissolved by the Prime Minister of Pakistan.