I think you can change your plan once per billing cycle through self-serve (free). And you can change multiple times per one billing cycle by calling or visiting koodo store anytime you want ($10 for one change).
If you have a tab, you need to make sure your plan stays in the requirements of your tab. For example, if you have any tab your plan must be at least 30$. If you have a tab large, you need one of the tab large plans.
I want to buy the new samsung galaxy note 8 and right now, I can get $250 off of the upfront payment, but I have to choose a tab large plan. does that mean I can't degrade my phone plan? or can I still degrade my phone plan?