We see the same exact experience also with a timesheet and find the need to have to recall the timesheet to be clunky and an unnecessary step. Microsoft probably has a reason but it is not documented. If nothing else maybe the experience could be modified so that (a) the Add Line option remains enabled, but (b) when the Add Line button in clicked in a Rejected status it would throw up a message that says: "This document is in a rejected status and must be recalled to add or remove any lines. Do you want to continue? Yes or No." If no, nothing happens. If yes, the recall occurs, AND a line is inserted. It would make the experience much better and avoid users calling the help desk to report that they "can't add or remove lines"!