Replace empty cells in schedules

hi all

Im trying to find and replace empty cells in my schedule but its saying the string cant be empty

I’m not sure if I’m following what you trying to do. But, if you just want to replace the empty comment values for other values, first just filter the elements, separating the ones that have comments from the ones that have empty comment, then just replace the empty values for the values that you want. Here’s an example: