When your existing mortgage term ends you will need to either pay it out in full, renew with your current lender, or transfer it to a new lender. Many people do not realize that they are able to transfer their mortgage when their term ends. Your current lender will send you a renewal letter and they will likely not offer their best term or rates and hope that you don't explore your options and sign.
It is important to know that you can secure your rate 120 days from your renewal date. Keep in mind when your renewal date is and contact your mortgage professional as soon as you can, to lock in your rate as early as possible.