license agreement says you cannot sell a solid\works license
The license can only be transferred in the event that the entire company is sold/acquired by another. You cannot sell the license.
Kenneth Duval - Welcome to the real world of surprise..... see this thread and read every reply SolidWorks "Expired Subscriptions" will be switching to a “full backdating” format 1/1/16 written by Rick McDonald - I know it's a long read, but you'll understand the value of your 2015 seat rather quickly... It has no value at all, there is no equity in owning a seat of SW, unless it is still within the subscription and it is only transferable if you are selling a company and have SW as one of the items for sale etc.. then your VAR would help you with the transfer..
Did you purchase this seat personally or do you own a company that you purchased it with?
As Jaja Jojo. Jeff Holliday and John Stoltzfus have all said, you can not sell a license, unless it was originally purchased through a company (so it is considered a company asset) and is part of a complete sale of that company.
You would have to involve your VAR / SWX to verify it was a Company sale and they would transfer the license to the new owner/company.
Another issue is the Backdating policy as John mentioned. How long has it been off subscription?
If it was part of a company sale and it has been off subscription for 2 years (assuming you got it in the beginning of 2015 and had a 1 year sub. then it would have been off for all of 2016 & 2017) the new company would have to renew the subscription and pay 2 years of backdating ~$3500 just to be at the same place as they would if they purchased a brand new seat. You would have to almost give it away in the deal for it to make sense to consider it a company asset.