Temporary Resident Visa (TRV)is what you need to enter Canada for Countries that aren't listed under Visa Exempt category. Once you enter Canada using the TRV, an immigration officer will then stamp on your passport a Temporary Resident Permit (TRP). It should contain information such as how long you can stay in Canada (if its less than six (6) months or most of the time it doesn't show the expiration which should mean 6 months (no more than that). Unless you apply for an extension before your TRP expires (30 days before).
So, to answer everyone's question: :'(YES YOU CAN APPLY TO CHANGE YOUR STATUS, but it depends on what situation you're at. consider things like finding a job, LMO processing etc.
Changing your status after coming to Canada as a visitor
When you arrive at the port of entry in Canada, a Canada Border Services Officer (BSO) will stamp your passport or travel document and record the date by which you must leave Canada. The BSO will also note any terms and conditions related to your visit. There may be times you wish to extend your visitor status or change the conditions of your visit.
If you wish to extend your status date, you should apply 30 days before your status expires in order to do any of the following:
extend your visitor, student or work status
change the type of permit you hold (for example, from a student to a work permit)
change a condition of your permit (for example, if you are studying and you want to change schools, or if you are working and your want to change jobs)
Detailed information on how to apply to extend your stay is available on CICís www(dot)cic(dot)gc(dot)ca/english/visit/extend-stay(dot)asp#extend
He still cannot switch from Temporary Resident Visa to Work Permit. Temporary Resident Permit (TRP) is not the same thing as a Temporary Resident Visa (TRV). The TRP is given as an exception to those people who are inadmissible to Canada. See the link below: