Yes, you can select a different plan at any time.
To change your subscription plan:
Login to your Supliful account.
Click on your avatar in the top right corner and select Subscriptions from the drop-down menu:
You will be taken to the Stripe subscription management page. On the right, click Update Plan:
On the new page click Continue next to the subscription plan you want to switch to:
Stripe will automatically calculate the amount that was already paid and used for the previous plan and extract the unused funds from the new plan price:
Click Confirm, and the new subscription plan will be applied to your Supliful account right away.