I am having a hard time understanding what you are doing here. Can you try describing what is happening again in a different way? I think when you say tabs you mean tables in the table bar.
Here is my assumption of what you mean:
You created a new field in a table, we will call this Table A.
You would like to have this new field added to a specific report that is on Table B instead.
Is that accurate? If so, can you let us know what relationships you currently have set up and also detailing the tables you have may help.