Due to the nature of items on a template it is not possible change between template item formats so it is necessary to delete the original and create a new one in the required format. 

This Tutorial focusses on changing a Number item to a Text item but the process is the same to change anything (eg text to email address, whole number to decimal number, etc).

1. Open the template list from Maintain Templates in the Setup/Maintenance menu.
2. Identify the required template from the list and right-click to get the context menu.  Select duplicate to create a copy before you make any changes.
   
3. Identify the item that needs to be changed from number to text and make a note of the unique name
4. Right-click on the item and select Delete from the context menu.  Confirm.
   
5. Click on the Add Item button and select Text from the menu pop-up window.
   
6. Enter the Question as in the original.  There is no need to save until after step 7.
   
7. Click on the Advanced tab and enter the unique name as noted in Step 3.  Save.