Yes!
You can actually move your renewal to today directly in your account.
1) In your dashboard, click on My Subscriptions.
2) Locate the prescription you'd like to renew and click "Manage Prescription."
3) Click on "Running low? Ship now." On mobile this will be at the bottom of the Manage Prescriptions page and on desktop will be in the upper right hand corner.
4) From here you'll be able to confirm you want to be charged today and your order will be shipped within 2 - 3 business days.
If you are looking to make any changes to your current prescription like adding more packets per month, you would need to click on "+Add refill" to select your new prescription and cancel this current one.