ladybeemer,
My first tire removal I had the same problem. It was too tight a fit even when tilted. "Steering" it to the left helps enough to get it out with a simultaneous flexing outward pull on the muffler by your assistant. You gotta move real slow to stay aware of the wheel paint scratching danger against the FD. That's the drill if you absolutely hate to loosen and move or take the muffler off.
Letting the air out might work for taking the tire out -but- complicates putting the new wheel on if you don't have a compressor or pump. You might just as well take the muffler off.

Speaking of taking the muffler off, there's a round of frustration

waiting for you there unless you know the routine. It will help a lot if you know certain operations will require specific directional forces greater than you anticipated. Take the top hanger 7mm Allen head bolt off that's hidden on the wheel side of the frame. Then loosen the 15mm nut on the exhaust clamp at the bottom of the muffler several turns. You may have to tap the open ends of the clamp with a small hammer so it unsticks from it's tightly squeezed and corroded-in-place position. It'll pop loose,
then you can wiggle & turn the muffler as you remove the clamp/heatshield assembly rearward along with the muffler, but slightly separated from it about 1/2". It may take a lot of man sized forceful wiggling/turning/pulling on the muffler outlet end until it finally breaks free. Now you can really clean everything good and give it a good car wax job.
After the new tire is on, if you have or can borrow a 2" long bead squeeze of Hi-Temp RTV Silicone gasket sealer for the exhaust joint, it will ease the installation, prevent all those little backfiring pops -and- totally eliminate those gazillion little black carbon specks on the wheel's silver paint. Coat the outside of the male pipe and inside of the muffler inlet so the muffler female pipe's expansion slit is filled solid with the sealer. You might think the sealer will smoke and catch fire when the bike runs, but it doesn't. Just allow it to set up, like overnite.
The heat shield has to travel forward WITH the muffler, partially plugged on as you install it, otherwise you will have great difficulty putting them together as the clamp will be around the corner of the pipe's bend and it's insertion point will NOT line up correctly. This little secret initially escaped me until I gave it a closer look and figured it out.
Prior to your riding the bike, remember to pump the rear brake till the pads clamp the rotor and you get a hard pedal.
I do not recall giving this much of a detailed muffler remove/install instruction before, but all will certainly benefit and Linda will be less frustrated and more willing to work on her bike the next time.
.