What was the date from which these changes took place?
The date from which these changes took place is not explicitly mentioned in the provided context. However, we can deduce that it occurred on 1st November 1956 based on the following information:

- Article 258A was inserted by the Constitution (Seventh Amendment) Act, 1956, s. 18 (w.e.f. 1-11-1956).
- Article 259 was omitted by the Constitution (Seventh Amendment) Act, 1956, s. 29 and Sch. (w.e.f. 1-11-1956).