When asking questions on the site, it is best to use Canadian accepted terms for the most accurate answers.
I assume you are asking is it easy to switch between Regular Force (RegF) to Primary Reserve (PRes), after a short service in the RegF?
Answer: It depends on your terms of service when you join, generally speaking:
- If you join for a bonus, then you must serve the years agreed to.
- If you join for an education, then you must sereve the years agreed to.
- If you join straight in, then normally you are offered a BE, or three year contract.
Finish that and you can chose not to resign for a new contract.
Your question has been asked multiple times on this site.
Searching would have provided your answer.