Change in use of principal residence

My client has recently changed his principal residence, he moved to a new house and made that new house his primary residence, and the previous house he was living in, has been put up for rental.
Now he is asking me, should he be filing T2091 for change of use and get the fair market evaluated for the old house to avoid excessive gain at the time of sale.

Can you please suggest how to deal with such situation?

Sounds like your client already did the homework, so a simple yes?. Unless you want to get into what if and how about, then you get into 45(2), maybe save some taxes, but you don’t know until you do a full analysis