Ultimate Membership Pro – automatically cancel previous subscription

Hey everyone,
I am using Ultimate Membership Pro to sell monthly subscriptions to my users.
but here is my problem: I give a free subscription level to my users when they first sign up. then they can buy a 1-month subscription after they log in to my site. but when they buy this 1-month subscription, I want their previous subscription which is the free one to be canceled and the 1-month to be activated as their only subscription level.
But the issue I am facing now is after the purchase, users have 2 subscription levels. one is the free fon and the other is the 1-month they purchased.
Is there any way that I can do what I described?
Thanks in advance!