I would suggest the following system:
1. Every existing season ticket holder is allocated a seat that is representative of where they are now.
2. The club hold an open evening where fans can walk around the new arena and look at where their seat is. This allows them to check there haven't been any mistakes and also allows fans to see if they would prefer to sit somewhere else.
3. All existing season ticket holders then get a set period of time to move their seat to an alternative and available seat. Say a week or a fortnight. Perhaps allow an extra day or two at the end in case somebody then wants one that has just become available.
4. The remaining seats go on sale to new season ticket holders.
1. Every existing season ticket holder is allocated a seat that is representative of where they are now.
2. The club hold an open evening where fans can walk around the new arena and look at where their seat is. This allows them to check there haven't been any mistakes and also allows fans to see if they would prefer to sit somewhere else.
3. All existing season ticket holders then get a set period of time to move their seat to an alternative and available seat. Say a week or a fortnight. Perhaps allow an extra day or two at the end in case somebody then wants one that has just become available.
4. The remaining seats go on sale to new season ticket holders.