U can just make the changes and send email to the editor this can be done at proofreading stage also. Sometime they may ask for the contribution from each author.
Author's contribution should be defined properly to the editor during revision stage. However, it is not a good practice of adding authors name or sequence of authors except it is very important to add the author for the significant contribution made in the manuscript for final publication.
You can also revise the author section during your revision or proof reading: and it can be in the form of adding another author who may have helped with a very major revision, or change of address, or even removal of an author from the list. All these changes can be done before early bird view or publication. After publication, no such changes are allowed
Dear Dr. Mohammd Rafiq, Ashish K. Chaturvedi and Kwamina Ewur Banson:
Thanking you for your valuable inputs, during revision we are unable to update or edit the name of authors. Please see following options showed and we are able to work on Article Info onwards not in the Journal Info and Author Info
· Journal Info
· Author Info
· Article Info
· Editorial Info
· Upload
· Payment Info
· Preview
Please suggest any other option, thanks once again for your nice cooperation.
You can change it by writing to the editor and while uploading the revised file you make sure to keep all the authors. Some journals also provide the freedom to change all the details during a revision starting from title to acknowledgement. If in your case its not a option you should write to editor and keep the name of author you wish to change in your manuscript file.
The easiest way, contact the Editor and tell what you want. They will contact you back and you just follow their instructions. I do this when I feel lazy to read long descriptions.
You can update the author details in the paper while sending its final version and you can request the chief editor to consider the updated version of paper for publication.