Change a drop down field into a text field?!

We need to change the type of field we added manually to the registration form, specifically a one selection-drop down list field into a text field, knowing this field already have data in the database entered by a caseworker, would it be possible to change the type without effect or loss of the already entered data?!!
We need to keep the previous data and change its field into a text that most satisfies all our partners’ needs.

I would hide the current field (do not delete it). Then create a text field with the same Label as the previous hidden select one but with a different database name and make it visible. It is generally good practice to hide/show stuff rather delete anything

Thats eaxtly what I was thinking of, but the point is what about the already stored data?!

The data will remain in the database. If you need access to it you can export the records before the change. Any new records created after it is hidden will not export the data any longer