Adjusting drawings during construction

Adjusting drawings during construction: if the drawings are handed over, and when contacting the construction side an adjustment is needed (the original material is not available, or the cost rises too high, or it cannot be done as designed...), is adjustment supported (even if charged)? What if the drawings sit for 6 months or 1 year before being used for construction and the above issues arise? Design-construction coordination for plumbing and electrical: how can the design company and the construction company work effectively on electrical / water lines and materials - especially when the construction company is chosen a few months after the design is finished?