How to change or update select list of field which is already filled with values How to change or update select list of field which is already filled with values.
When I try to remove or edit value the options, I got:
"Allowed values list: some values are being removed while currently in use."
That's quite a daunting task - in order to keep consistency of existing values already stored in your database you can either change all of the nodes containing the value you want to change or add a new option to the select-field.

Changing a lot of options at once could be done by a views-bulk-operation and the operator Change value (not sure, if it's called this way - but it exists ;)).

If i run in such a situation i often write an update_hook to change all values of the field in the db (do not forget to change revision table also) and change the select values afterwards.