>i am using auto increment to assign a number to a field automatically. However, every now and again, I need to change the number manually in the data. It's not allowing me to do so, says it's read only. I end up having to hit cancel and killing the application to get out of the routine.
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>More details;
>I have consecutively numbered membership cards.
>Each record has a unique card number assigned to it.
>If I create a new record, then revert changes back, it increments the count ahead, even though a new record was not created.
>So I have a useless membership card, unless I can go back and manually input the correct member number, that has already been passed.

That's the nature of the auto-increment field. You can not update it manually and it can skip numbers if the changes were reverted.