+1(514) 937-9445 or Toll-free (Canada & US) +1 (888) 947-9445
Do you mean put it on hold without paying for it? If so, then to the best of my knowledge it's not possible.
 
If you know a travel agent, they could do it. But it wont last long enough. There is a period after which the system releases the blocked tickets automatically. Most of the travel agents do this favor, if they know the person and dont hold tickets more than couple of days.

lovely21 said:
Hello Friends,

I need to block an air ticket for Canada ? Can it be done and how ?