Discussions are asynchronous by nature, meaning that students typically are asked to respond over the course of a few days to a prompt that was created for them in advance. Since students will all have several days to respond, often special accommodations are not needed, unless the student is unable to participate during the set timeframe. In essence, the student will need an extension, not an accommodation.
If Discussion topics in a course have start and end dates, and there is a student who needs to participate beyond those original dates, Instructors can either remove those dates or change the dates to allow the student to participate through a later date. Changing these dates will change for the entire class.
As a reminder, start and end dates control when a discussion is available for students to see, with further options to control when they are able to respond to and participate in a discussion topic.
Review the following resource to Set Availability and Due Dates for a Discussion Forum or Topic.