I contemplated withdrawing an application and I got this response from CIC:
Sir, Madam,
Thank you for contacting Immigration, Refugees and Citizenship Canada. I am pleased to follow up on your request:
Withdrawal of application - Centralized Intake Office - Sydney
To submit a withdrawal request, you must send a signed withdrawal letter to the Centralized Intake Office (CIO) in Sydney, Nova Scotia, or fill out the IRCC Web form available on our website. Your letter/email must include the following information:
Your name,
Your date of birth,
Your address,
The date you sent your application,
Your client ID/UCI (if you have one),
The type of application (e.g., caregiver),
The reason for the withdrawal, and
A copy of the e-Payment receipt or a copy of both sides of the payment receipt form (IMM 5401).
If applicable, you have to write Withdrawal of Application on the envelope and send it to the CIO in Sydney. For their contact information, please visit our website.
The office will review your letter and let you know if your request to withdraw has been accepted. Please note that a withdrawal request will only be considered if permanent residence status has not yet been given.
The amount of the refund, if approved, will depend on the processing stage of your application:
If the processing of your application has not started, you will be refunded the total amount.
If the processing of your application has started, only the RPRF will be refunded.
If your withdrawal request is accepted, a refund should be issued within 16 weeks. If applicable, it will be given to the person identified as the payer. If it should be given to someone else, you have to give the name and address of that person in your request.