can I add another author in a revised paper?
The goal of revising a manuscript is to change it for the better. Revising might ask for few changes, or it could need making “large, sweeping changes, reorganizing part or all of the text, significantly adjusting tone and voice, or adding and removing chunks of text, as well as fixing grammatical errors.” Revising might be done by the author, the journal editor, or peer reviewers, who are experts in the applicable subject. During revision of a manuscript, authors may need to carry out additional experiments or studies in order to address the reviewer comments. In that case, the contributor of the experiment needs to be acknowledged in the manuscript. Usually journals don’t have any issue in the number of co-authors added in the paper. However, you must mention in your cover letter as to why the contributor was added as the co-author in the manuscript, along with the contribution and why it was essential. You can check through the author guidelines for further information. In case your paper has multiple co-authors, besides the cover letter, you might need the consent from these co-authors regarding the addition of another author during the revision.
In case you need help with revising your manuscript and submitting it to a new journal, you can check with Enago’s Revised/ Rejected Paper Editing service which will be helpful to revise your manuscript according to the reviewer comments and submit to the same or new journal.
