You can pause activity for upcoming payments by selecting the payment from the Upcoming Payments card and tapping the three dots in the top right. When you pause an active payment, you won't see any new roundups or withdrawals for that specific payment for 30 days.
Withdrawals already initiated that were not canceled individually will still go through. Additionally, it does not pause the actual payment from sending out on the scheduled date.
Keep in mind that activity will resume 30 days after paused. You will receive notifications periodically reminding you of this.