ticket expiration

So I am a veteran and am able to take advantage of discounted tickets through Shades of Green. I am not staying there but can still purchase discounted tickets. I was going to send in the form and have them mail them to me (which I know takes time). My trip is planned for the end of July so...

I will first apologize for posting a question that I am sure has already been answered. I looked for about 10 minutes and could not find a direct answer. I purchased tickets through a 3rd party (Und. Tourist). They are set to expire in 2021. Can I use the value of these tickets toward 2022? We...