Is It Possible to Reduce Ears from 7cm to 5.5cm?

There are no good procedures for reducing the vertical height of your ears.
If they stick out too far, Otolplasty Surgery will bring them closer to your head so they're less noticeable, and won't stick out as much.
I see you have loss of your anti-helical fold which is easily restored with Otoplasty Surgery.
Consult a board-certified facial plastic surgeon experienced in this procedure.
I've attached a link to my Otoplasty photos for your perusal.
I hope this is helpful for you.

You are really a great candidate for ear shaping surgery or Otoplasty.
A few things:
1) Make sure you go to someone who has good experience with this. This is essential to achieve a natural result.
2) Re-creating the fold in the ear is done with Mustarde sutures and is usually very reliable.
3) Shorten the length of the ear is also achieve able. This requires a bit of finesse and I do this with a "star-plasty" of the lobe. This allows the long lobe (bottom of your ear) to be shortened with minimal scarring and a more natural shape.
Best of luck!

The costs for otoplasty varies significantly around the country. Our cost for otoplasty ranges from $2500 to $5000 + MD Anesthesia Related Costs (if necessary). More expensive cities such as New York or Los Angeles or areas with fewer board certified plastic surgeons may be more expensive. To maximize value while maintaining quality, consult with board certified plastic surgeons that own their own AAAASF nationally accredited facility, These surgeons must maintain the highest quality to keep the accreditation, have greater incentive to ensure a higher caliber of staff who detailed knowledge of plastic surgery procedures, will maintain comfortable and safe operating facilities to maximize patient referral, and ensure minimal waste to keep costs to a minimum.Consult with 3 experienced and expert board certified plastic surgeons to understand your options.