When live scoring for a game in PlayHQ's Electronic Scoring portal, player positions provide the ability to make substitutions throughout any stage of the game (rolling subs and intervals).
To commence a substitution, you will need to select Positions in the bottom left-hand corner.
In the resulting pop-up window, select Remove (trash icon) on the player being subbed off, and the player being subbed on.
Then select the position at the top of the window and 'apply' this to the relevant player. You will also need to assign 'interchange' to the off-coming player. Once the player's positions have been set, select Apply to proceed.
You will now arrive back on the scoring page with the updated positions.