If I am asked to shorten a garment with pleats, I will always discuss what will happen to the client first. They need to have two options put to them.
The first option is shortening from the bottom, HOWEVER they must understand that they will have to take it to a drycleaner and have it RE PLEATED.
When it is shortened from the bottom, the pleats will be going in the opposite direction, which means they will spray out. This is not something that I can do, and I would recommend you leave it do the experts on pleating.
The second option is to shorten from the top, which means the waist. Depending on the construction of the garment, this is almost like a remake, and I explain that I work on AUD$40 per hour, and this type of alteration can take up to 4 hours or more. which cut be up to AUD$160.00. I do state that this is the worst scenario, and it could take less time, but it is not a quick job.
That means they have the option of having it shortened from the bottom which would be around AUD$35.00 (approximately) or the second option which is more expensive.
Do suggest that they get a quote from a drycleaner to re pleat as this can be expensive.
Judith aka genie