You'll need to post pictures so we know exactly what you're talking about.

When you're asking for help, you need to be very specific on the terms you're using.  

Example:
You start out talking about a Correspondence Form, then later it sounds like you're referring to a "Form that shows records from Reports"?  This is why it's good to use the Conventions Rick uses when naming Forms and Reports.  All the table names, form names, and report names start blending together, especially for someone who's not looking at your database.

Each form in this thread is named for its underlying table.  That would not necessarily always be the case in every situation, but it IS the case here.  A form that shows records from Reports, that would be the Reports form.  The Correspondence form shows records from the Correspondence table.  I want a button that is on the Correspondence form to generate a new related record in Reports, carrying over certain field information from the Correspondence record that was the active record when I clicked the button.

Do you still think you would benefit from a screen shot or entity rel diagram?

Your description requires anyone to make a whole lot of assumptions on how you've built your database.  Making blind suggestions will not help you.

There's not much built — I'm replicating in Access what I have in FileMaker and mostly I have tables defined with primary and foreign keys, and relationships, and I have some very rudimentary forms, one each for the relevant tables.  The button I'm trying to implement is the first element of any complexity.

Feel free to ask questions.  I'll probably learn as much from the questions you ask as from anything else.