Plans can change, but please do be respectful and ensure that you contact the client to let them know as soon as possible about a cancellation.
Be aware that cancellations, especially late or without good reason, may lead lead to a bad review which will affect your ability to find future work.
After a project has been offered and agreed, you should provide at least a days notice to cancel.
It's good practice for clients to confirm receipt of a cancellation and it's an excellent opportunity to rearrange the date of the job via the Grafter service.