Is it possible to change something on a research paper between the period of acceptance and publishing? My paper was accepted in peer reviewed journal last week and is about to be publishing. Last night I thought the solution makes better sense if I change the definition of one of the variables. This is a minimal change which doesn't change any of the other equations or any of the conclusions or results. 

Is this possible and how can I ask If I could change this variable?

Also, if they accept does that mean that the paper has to to be reviewed again?
My advice is to contact the editor of the journal and ask about your desired change. The editor may send it to one of the reviewers, or may accept the change without further review. But communication with the editor is what you need.