Can Rise be purchased separately?

Typically after an elearning project is complete it needs to be reviewed by the SME who often makes changes to the wording of text. With only a handful of accounts it's not possible to do this, so the elearning developer has to note the changes, apply them in Rise and then ask the SME to review again. A possible solution to this would be an account type that could be used by the SME for flagging edits (i.e. like track changes or review in Word).