How long will you be gone for? There are a few options. You can schedule a callback with Koodo and ask them to place you on the seasonal hold plan. This will cost you $15/month to keep your number active.

Alternatively, you can port your number to a prepaid service or VoIP. For example with 7-11 Speakout you can keep your number active for $25/year. A VoIP service would probably the same cost, but a one time fee rather than per year.

Here is info on the seasonal hold plan: 

https://www.koodomobile.com/en/help/keeping-your-account-open-when-travelling

You’ve got a few other options. Since it’s 15 dollars a month, you can :

switch to the 15 dollar starter plan; the 15 dollar prepaid plan, which allows you to top up every 89 days (90 days and account cancels) and ends up costing about a third of the price that way; or you can port your number over to a voip provider. It costs 10-30 dollars, and often there’s no monthly fee. This way you can continue to use the number with an internet connection if you wish. These other options I believe require paying off your tab if you have any. So as long as it’s zero or close to zero, I think it’d be worth it.