how can i add automation on priority, that it can be reset rest of ticket on updating priority

[Anum]

My priority dropdown holds Numeric Values (1,2,....) how can i add automation in such a manner that priority can be set automatically, and if any priority is updated, rest of them gets updated automatically

Example,

I have ticket logs 10 in my a queue, with priority 1- 10, now I log 11th ticket and want to give it a priority as 1 instead of 11.
on changing It to 1, the previously prioritized ticket as 1 moves to 2 priority and previously 2 moves to 3 and last 10th reaches to 11 priority.

how can i achieve this?