You're probably already aware that here in the UK there is a three month period between the first and second vaccinations. I received my first Pfizer jab on 16th February and the second was scheduled for 11th May.
This morning I received a text informing me my May appointment had been cancelled because they had an earlier appointment for me and I should ring the number in the text.
Took me five minutes in a call queue and was informed my new appointment was 6th May, five days earlier