If you are going to take in a garment at the zip, pin the garment at the pin with the zip closed.

When you have finished pinning, move the pin across to one side only at the zip area so that the person can get out of the garment.

Don't pin darts in a garment, then take in at the zip.  Always pin where you are going to alter the garment.

Happy sewing

Judith aka genie