Do MPs represent their riding or their region?
Both! The MPs are elected by the region as a whole and represent the entire region on matters of policy. Residents of the region should feel free to contact the MP they feel is best to represent their policy concerns.
Each MP also represents a specific riding. Residents of the riding should contact their local MP for strictly local matters (e.g. economic development) or for help (e.g. immigration for a family member).
Would an MP’s title change?
The dual responsibilities should be reflected in their title. Rather than “MP for Kitchener-Centre”, we would have “MP for Waterloo Region (Kitchener-Centre)” to reflect both”
Which MP would I go to?
Constituents and their MPs typically have two relationships, one centred on constituency support and one centred on policy. The first relationship is about “I need help with…” while the second one is about “we need a law that…”.
Constituents would typically go to their local riding MP for the first relationship and for local issues such as economic development. For the second relationship, constituents would typically choose the MP from the region that they believe would best understand and advocate for their position. They might also choose to go to an MP belonging to the party they supported in the election.