Single-Selection Radio Button to Multiple Selection Checkbox ?

[Suri.CMS]

Hi All,

I created a custom field (in user registration page) that is Single-Selection Radio Button.

Now, I want to change it to Multiple Selection Checkbox (Options remain same as before).

Is there any way to do it without losing the data ?

(I don't want to delete and recreate the User Profile field. Because I already have so many members and the data of this User profile field is important.)

Example:

Custom Field: Please select your location.

- Boston
- California
- New York

Currently users can select only one of these locations.

Now I want users to be able to select 1 or more of above values.