Here is the answer to your question according to the SS site:

What is a Ticket?

The Ticket to Work Program is an innovative program for persons with disabilities who want to work and participate in planning their employment. A Ticket increases your available choices when obtaining employment services, vocational rehabilitation services, and other support services you may need to get or keep a job. It is a free and voluntary service. You can use the Ticket if you choose, but there is no penalty for not using it. You might not be subject to a continuing disability review while you are using your Ticket.
Where can you use a Ticket?

This program is available in all 50 states and 10 United States Territories. Many SSDI and SSI disability beneficiaries will receive a “Ticket” they can use to obtain services from a state vocational rehabilitation (VR) agency or another approved provider of their choice. We call these approved providers “Employment Networks”. Employment Networks (ENs) are private organizations or government agencies that have agreed to work with Social Security to provide employment services to beneficiaries with disabilities. The EN you choose will help you activate your Ticket.
Where can you get
more information?

For more information on Ticket to Work, including a list of approved Employment Networks, contact the SSA Ticket Program Operations Support Manager, MAXIMUS, at their toll free numbers: 1-866-YOURTICKET (1-866-968-7842) or for TTY/TDD call 1-866-833-2967 between 8 a.m. to 10 p.m. Eastern time (Monday through Friday).

Information about the Ticket to Work Program can be found online at
www.ssa.gov/work/aboutticket.html or www.yourtickettowork.com.