You can hardly change your name unless though marriage ... or adoption.
http://www.cic.gc.ca/EnGLIsh/applications/guides/CIT0001E4.html
Section 3
Indicate your surname/last name and given name(s).
If you are applying to replace your certificate, your name will be the same as what was on your previously issued certificate. If you want a different name on your replacement certificate, you must provide us with satisfactory documentation.
If you have legally changed your name, we require a copy of the provincial or territorial change of name document.
If you have changed your name as a result of marriage, adoption or divorce you must submit a copy of that document showing both names. In addition we require one provincially or territorially issued document, such as a health insurance card, driver's license or an official school record issued by the provincial or territorial Department responsible for education showing that exact name. Your certificate will reflect the name on your provincial or territorial document.
If satisfactory documentation is not provided to support the requested name change, your citizenship certificate will reflect the name recorded on your previously issued certificate.
If this is the first time you are applying for a citizenship certificate, the name on your citizenship certificate will be the same as the one shown on your birth certificate, Record of Landing (IMM1000), Permanent Resident Card (PRC), Confirmation of Permanent Residence (IMM 5292), or foreign passport.
If you have legally changed your name, we require a copy of the Provincial/territorial change of name document.
If you have applied for an amendment to your Record of Landing, or Confirmation of Permanent Residence, we require a copy of that amendment or a letter confirming the change of name.
If you are requesting a different name as a result of marriage, adoption or divorce you must submit a copy of that document showing both the old and new names. In addition we require one provincially or territorially issued document, such as a health insurance card, driver's license or an official school record issued by the provincial or territorial Department responsible for education showing that exact name. Your certificate will reflect the name on your provincial/territorial document.
Note: If satisfactory documentation is not provided to support the requested name change, your citizenship certificate will reflect the name recorded on your birth certificate, Record of Landing (IMM1000), Permanent Resident Card (PRC), Confirmation of Permanent Residence (IMM 5292), or foreign passport.
If you have used other names in the past, or are known by a name other than the one you listed above, indicate them in the space provided. (Other names can include your birth name, nicknames, call names, community name, etc.) You can use a separate piece of paper if required.