Rohin Roy Dheer said:
Today after applying visa for Dalhousie University, when I came back home I found that TCS person was standing by my door he gave to courier. When I open courier there was admission letter of Ryerson university for me. :-\
Dalhousie is slightly better in ranking then Ryerson. Didn't the Ryerson university tell you about your admission via email? If you were told then I guess you wanted to join Ryerson University otherwise you would not have considered this LOA.
Whatever happens, it happens for good. Have faith, Inshallah it will be best for you.
1. You can update your LOA even after the medical call.
2. You can join Ryerson university even if you get your Study permit on the basis of Dalhousie University Provided you remain at same level of education (from master in one university to master in other university) you don't required modification in your study permit and you are not require to even communicate this change to CIC.
Source: Q 13 of FAQ (http://www.cic.gc.ca/english/information/faq/study/index.asp)