do u meant reply as approval? what i understand from my sponsor is, after submission to CIO or after 3 - 4 months, they will send another letter requesting or instructing for medical (MR) and eventually starting the counting of one year period when the result was submmitted back to CIO..the medical centers will submit themselves the result direct to CIO or VO. after 2 months they will request your passport for visa stamping..again the counting of one year validity will start when they submitted the result of the medical, therefore an applicant and his/her dependents (if, any) should be landed in canada within that period.
note: processing fee and permanent resident visa fee should be paid at the same time to save atleast 3-4 months of processing period.