Chlorine bonded with ammonia in a Chloramine compound, will not allow the chorine to evaporate out in any significant way, or reasonable time. When I worked as a chemist at a water company we tested chloraminated water that sat for 2 weeks and found no significant reduction in chloramine residual.
We "were" able to filter chloramine out using activated carbon, but the detention time in the carbon had to be very long, it had to be dripped so slowly thru a long tube, which is impractical for use in water changes Maybe enough could be dechloraminated to change water using a 24 hour drip for a 1 gallon betta bowl.
Using one of the commercially available dechoraminalors is the only efficient way I know of.
If money is the sticking point you can use the dry form of Prime (Safe) made for ponds, and mix your own, or even cheaper buy a bucket of sodium thio-sulphate salts from a local chemical supply company. Sodium thio breaks the chloramine bond, removing the chlorine but leaves the ammonia. My biofilters were always oversized and easily handled the ammonia bump, and because I always added the chloraminated water to sumps as opposed to directly into the tank, this also helped. A 5 gallon bucket of sodium thio is not cheap, but lasts forever. Sodium thio was practical for me because I had 3000 gals of tanks, but may be impractical for the average aquarist.