If you are having difficulties with using this facility on the Mitel phones then please click on the link below which will take you to the IT User guide. This was something you would have been given during your initial IT training. You will find within the guide instructions on how to use the Mitel Phone, including putting people on Hold.

https://carerssupportws.sharepoint.com/sites/changeprogramme/IT%20Resources/Forms/AllItems.aspx?viewpath=%2Fsites%2Fchangeprogramme%2FIT%20Resources%2FForms%2FAllItems%2Easpx&id=%2Fsites%2Fchangeprogramme%2FIT%20Resources%2FUser%20guides%20and%20training%20resources%2FMitel%20phones%20user%20guides