"Branches: Executive--Queen Elizabeth II (head of state represented by a governor general),"
http://www.state.gov/r/pa/ei/bgn/2089.htm
Procedures for Dissolution
The prime minister traditionally visits the governor general at Rideau Hall and submits an instrument of advice to the governor general recommending dissolution. An instrument of advice is a written document from the prime minister requesting that the governor general authorize a constitutional or legislative action of government. The signing of the documents normally takes place in the governor general?s study. When a dissolution is agreed to, the documents are signed in the following order:
1. The prime minister submits an instrument of advice to the governor general recommending the dissolution of Parliament by instrument under the Great Seal of Canada. The governor general signs the instrument indicating his or her approval.
2. The governor general signs a proclamation in the name of Her Majesty the Queen dissolving Parliament. (The deputy registrar general of Canada and the deputy attorney general of Canada sign the proclamation prior to its submission to the governor general.)
3. The governor general signs the minutes of a meeting of the Privy Council authorizing the issue of election writs fixing the polling day and the date of return of writs. Election writs authorize the conduct of elections in electoral districts.
4. The governor general signs a proclamation in the name of Her Majesty the Queen declaring that election writs are to be issued. (The deputy registrar general of Canada and the deputy attorney general of Canada sign the proclamation prior to its submission to the governor general.)
5. The prime minister submits an instrument of advice to the governor general for the issue of a proclamation for the pro forma summoning of a new Parliament. (Pro forma refers to the date that is set for the summoning of Parliament by the prime minister when dissolution is granted by the governor general. The date can be delayed further but it must always be at least a day after the date for the return of election writs.)
6. The governor general signs a proclamation in the name of Her Majesty the Queen for the pro forma summoning of a new Parliament. (The deputy registrar general of Canada and the deputy attorney general of Canada sign the proclamation prior to its submission to the governor general.)
Procedures after Dissolution
Immediately following the granting of dissolution of Parliament, the governor general informs Her Majesty the Queen of the dissolution and of the date set for the general election.
Election writs for each of the 308 constituencies are then signed on behalf of the governor general by the Secretary to the Governor General who is the deputy to the governor general and by the chief electoral officer.
A minimum of 36 days is required by statute between the date of issuance of election writs and the polling day. The date for the return of writs should be at least 21 days after polling day.
Polling day cannot be earlier than the nearest Monday (or Tuesday, if Monday is a holiday) after the 36th day following dissolution and the proclamation of the writs.