How to mend broken vintage pattern pieces

Everyone who has at least once attempted to sew a vintage style using old patterns probably found themselves in a situation, where they had to repair a damaged piece. Today I will tell you how I mend my sewing patterns. The main problem with repairing these patterns is that they have to remain fit for ironing.

This is a fabulous style with open back but the previous owner decided to make
an alteration and cut the main dress pattern piece.

This is the pattern before mending.