When you subscribe to a plan, you can cancel your subscription at any time.
The option is available here (Manager website > My Account > My subscriptions).
Once the subscription is cancelled, your account will stay active for the already paid period.
For instance, if you take a monthly subscription and only need it for one month, after subscribing you can click on "Cancel this subscription". This way, you can make sure the subscription will only run for the paid month, and you won't be billed again afterward.
Once the subscription expires, your models stay on the account, they are simply locked and displayed as unavailable. This allows you to come back anytime and find your account as you left it, ready to use.
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Looking for cancelling your free trial ? This option is not available, as it won't convert automatically as a charged subscription (your payment informations aren't asked during the free trial). Once expired, it simply locks the account.
You will need to manually upgrade the subscription to continue using Augment.
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To learn how to purchase a subscription, check here.
You can find all informations regarding subscriptions here.