SWITCHING from Tier 4 general Student Visa to tier 5 Youth Mobility visa

Hello!
So I am wondering if one can switch visas before one expires? My general student visa expires in October 2019 but my school ends long before then and I want to begin being able to work in June. I am requesting a Youth Mobility Visa that starts in April which would mean before my Student visa expires. Do they allow this?? Will it just cut my student visa short and replace it with Youth Mobility? I would have a few weeks of school left after my requested visa date, but I was the under the impression I could still study on the Youth mobility Scheme. I am an Canadian/ American and will be applying from the U.S. I also wonder If my application gets accepted for an April start date, will they not let me back into the UK to study until that April start date or will my student visa Be in effect until then? Thank you for any helpful information you can share!

Your student visa will be cancelled when a tier 5 is approved and issued.

You can re-enter the UK from whatever the date of your new visa is.

Should be no issue to enter the UK as long as you have a valid visa.

You should speak to your current sponsor as once your tier 5 is cancelled, they are no longer your sponsor.

Thank you so much! However I If to apply for it in February for it to start In April, and it got approved for April, would I still be able To enter and leave the U.K. before April with my student visa or would my student visa be cancelled For that time between February and April?
Thank you!
Mia

Likely it will be cancelled.

Thank You much!
Mia