You'll receive a Notice of Hearing or a Notice of a Preliminary depending on the complexity of the issues in question, in the post, as will the respondent. If you cannot attend on this date, you need to contact the Tribunal Office as soon as possible to request a postponement. You'll need to state the reasons for this request and also send a copy to the respondent. An employment judge will rule on whether you can be granted a postponement or not, and you will receive a new Notice of Hearing if they rule in your favour.