When you have been invited to be a Reviewer on a Call, once you have accepted the invite, you can specify your availability to be considered while in the assignment process.
From the Calls menu, locate the call to update and click the Call tile.
Below the About section, locate the Review Availability section
Select Phase availability either by clicking plus/minus (-/+) or manually typing the numeric option in field
If desired, you can increase or decrease the availability at any time after saving. The change will be received immediately on the Administrator side to be considered for the review assignment.
/*Please note, if you have not been given the option to set your review availability, this was not configured by your system administrator.