How do I format checkbox output using summary tag?

hi,

i am trying to format the ‘summary’ output in the emails that i receive when a user submits a form. i have been able to figure out everything except how to format the values from checkboxes. they currently are displayed in the email on a single line with commas separating each selected option in the checkbox like this:

CHECKBOX NAME
VALUE, VALUE, VALUE

is there a way to have them display in list format or with simple line breaks like this:

CHECKBOX NAME
VALUE
VALUE
VALUE

thank you for any help you can provide!