Method for transitioning from a first process for producing a first polymer to a second process for producing a second polymer. The first and second processes each include contacting a principal olefin and a comonomer with a catalyst under gas phase polymerization conditions to form the first or second polymer. The first and second processes utilize the same olefin but differ in at least one of the comonomer used and the reaction temperature at which the polymer is produced. The respective first or second polymer is then contacted with a purge gas to remove unreacted monomers. The method includes changing the flow rate of purge gas from a first rate to a second rate defined relative to a flow rate and temperature used for an earlier polymer produced using the same comonomer as the second process.