PHP表单逻辑问题

I have a logic issue maybe someone can explain how I can achieve this.

1. I have 2 forms that work together.
2. Form 1 is required to get the lead in, its about 3 fields.
3. Form 2 is a pop-up after you click send from Form 1. Form 2 is optional.
4. Client wants only to get one email for their lead system.
5. I'm using PHPMailer, jQuery & Ajax for this.
6. I already auto-populate some of the data into Form 2 from Form 1 into hidden fields to include in the email.

The only thing I can think of is adding some kind of time limit. Don't send form 1 for 10 minutes, if form 2 is filled out then only send form 2 since it already has the info from form 1. If 10 minutes passes without form 2 being filled out send form 1.

If not maybe I need to some how reconsider how the UX works with only 1 form.

The question is, how do submit both forms but only include it one email if the first form is mandatory? I need a way to capture the second form IF it is filled out before the first one is actually send and merge them.

Any help is appreciative!

Thank you,

If the user declines the second form, you can send form one email by observing on an event that is triggered when the second form popup is declined, like observing on an onclick event of the second form close button.

If it was not declined meaning the user submitted the second form then collect all information from both forms and submit in one email