You can change your subscription plan and view the dates of your billing cycle here.
To change plan, simply select a new plan and enter a coupon code (if applicable), the click the Update Plan button.
Your new subscription will be pro-rated to match your billing cycle - the details will be shown on your next invoice.
If you need to change the billing card details for your account, enter the new details and click Save Card. These details will be used for your next invoice.
A list of your invoices are shown on this tab. Click the ellipsis (…) at the end of the row to download your invoice in PDF format.