The registration of a DOMAIN is a binding purchase. It is also not possible to change a registered domain in the case of a typing error. In this case, the desired, correct term must be re-registered.
If you have mistyped the DOMAIN (.ch,.li,.asia,.biz,.com,.info,.me,.name,.net,.org), you can cancel (revoke) the DOMAIN within 5 days of the registration date without the registration being charged. With all new gTLDs we can check for you whether a revocation is possible.
Important: With .eu, .de, .fr, .it, .at DOMAINs there is no right of revocation.