Downgrade from Unlimited Data

I currently have an unlimited data plan, but I think I can get by on the 100GB Data plan which is a little cheaper.

The unlimited plan auto renews on the 10th of every month, but if I switched to the new plan on the 5th for example, would that be the new auto renewal date or would it still be the 10th.

Thanks for any help.

Edit: I've just found the answer staring me in the face...

"The change will come into effect after your current plan resets on Wednesday 10th June".