"Yes/No" Data Types And Forms

So, I've recently discovered that I'm more of an Access newbie than I had fancied myself to be. Anyway, I find that I need help with part of an ongoing project.

In our agreements with our clients, we have a set of standard terms which we typically use. Some clients with better bargaining power can occasionally negotiate better terms. One of the things I want our database to do is pull up which clients use the boilerplate terms and which have special situations.

I have two tables:
1) Fields: ClientID (Autonumber - Primary Key) & ClientName (Text)
2) Fields: ClientID (same as above - Primary Key) & Boilerplate (Yes/No)

For the clients that do not use the boilerplate, I would like to input the terms that differ from the original. Now to my question:

Is there anyway in my form(s) to make it so if I answer "No" (the client has special terms), it will then allow me to enter the special terms in another box? Similarly, if I answer "Yes" (that the client has boilerplate terms) no special entry box is triggered?

I'm not sure if I'm making any sense, but I guess I can sort of liken it to a computer survey where you have the choice of 4 options or "other" and if you select "other", an area opens for you to type what "other" is.

Let me know if you have questions. I'm at a loss for how to explain or do this.