How to receive fields from another form

I use a form plugin called Gravity Forms. When a user clicks the submit form three fields can be sent dynamically to populate three fields in the Easy Appointment Plug-in:
name, phone and email. The problem is that easy Appointment does not accept what Gravity Forms calls the Redirect Query String.
In this case the string looks something like this: name={Name:1.3}&eMail={email:1.6}&phone={phone:1.6}
The instructions in Gravity Forms is to have the receiving form “Allow field to be populated dynamically”

I think that the problem is that Easy Appointments greys out the 3 fields, name, phone email) until the appointment date and time have been entered. So, I assume that the fields cannot accept entries.

Is there any way to get those fields to accept the query string dynamically?

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