In the US, the CDC has made the determination that the 2nd dose WILL be given 21/28 days after the first. Only in exceptional circumstances (supply problems, patient unable to be there, etc.), they allow clinicians to extend to 6 weeks.
Neither Alan, nor any of us, have the ability to change this, one way or the other. (BTW, I believe it is the correct decision, even though there are those in my family who I would wish could gain 1st shot 30% benefit)
As I said previously, I was ready to give up my first shot so my wife could get it. At the time, we weren't sure both of us had an appointment. But frankly, I'm not willing to give up my second shot for an unknown stranger.
I think if the people here complaining that if they were 75 with four or five of the comorbidities like I have that makes Covid even riskier for old people, they might think differently as well. Regardless, like you said there's nothing anyone of us could do about it. I had an extra appointment for my first shot that I tried to get transferred to my 80 year-old friend with Parkinson's. But they wouldn't;t allow it. So I had to cancel the appointment. It went back into the general pool.
If people here are so unselfish about these things, let them not ask for an appointment until everyone else got their shot. That's the only way they could prove to me their heart is bigger than their mouth.