If you are staying at the Banff Springs then moving on to The Chateau Lake Louise for a few nights you may drop off your rental skis at the Chateau rather than returning them to Banff.
This saves you having to go through the rental process twice and also saves you money.
Just let us know when you are renting that you would like to use this service. When leaving your skis at the Chateau give them to Guest Services or a Bellman and let them know they are for the Banff Springs.