For In Review preprints, please contact us if there is an issue with the order of the author list. Preprints that are posted through In Review have limitations on what can be changed.
If your manuscript is still under consideration at an In Review journal, you will also need to contact the journal to ensure that these changes are made to your submission at the journal.
For direct submissions, any changes to the author list will require a new version to be posted in order to make the changes - see How do I submit a new version of my preprint?