If it does detect a failing SSD; see if the error can be fixed with a firmware update to the drive. Make sure to check if the update is destructive or not, as a destructive update will irrecoverably wipe all the data from the drive.
If the drive is failing, and there is no software fix, then the swap out is either relatively painless, a relative pain in the arse, or actually impossible for the end user. All depends on whether it predates the period that Apple started to glue the components in and later switched to integrating everything on to the mainboard (i.e. RAM and SSD).