Field to pop in as an alert when pressing a button?

Hello, 

I have created a button to reject my quote when not approved by my client. 

Is it possible after pressing the button to have a pop up alert field where I could enter the reson for the rejection and once the reason is entered and a button ok pressed to have the rejection action done?

So far this is my formula, I press the button and the quote is rejected. I'd like a field pop in as an alert to enter the reason and then disappear if that makes sense: 

let result := dialog("Rejected", "Are you sure you want to reject this Quote?", ["Yes", "No"]);
if result = "Yes" then
'Status (Not to show)' := 9
else
if result = "No" then
alert("Action cancelled")
end
end

Thank you