You can change your contribution amount or switch between RRSP and TFSA in a few steps.
Editing your payroll contribution
1) Go to the Plan tab.
2) Under My contributions, select the "From paycheque" tab to open your contribution details.
3) Click Edit my contribution.
Edit your contributions
On the Edit payroll contributions screen, you'll see your current setup pre-populated. Enter your desired contribution amount. You can also view your employer match by selecting See matching formula.
Review and confirm
Click Next to review your total contributions (including employer match) and, if applicable, the split between RRSP and TFSA. Confirm to save your changes.