There are a few ways, however you probably don't need to do anything as they are similar questions, and the bot will automatically match similar questions.
You can also just add both questions with the same response, or you can label the response and use the label.
what are you going to do
I have big plans.
label: #plans
what do you plan to do
#plans
See,
https://www.botlibre.com/forum-post?id=12117061
You can also use redirects, srai, or patterns.
Pattern("what are you going to *")
Template("{redirect("what do you plan to " + star)}")
what are you plan to do
I have big plans.
or even just,
Pattern("what [do are] you [plan going] to do")
I have big plans.
