I need to change a multiple choice-text field to a text field and there is no option to change field type

There is a radio button in the field properties to change the input toe to user input.

But rather than do that, if you really do want to control the choices available le to Used, you can create a new table of choices and the key field to be the choice value. Then copy the existing choices onto your clip board, and use import export to import them into your choices table.

Then make a relationship to your data table. Then you can have unlimited choices and also users will be able to search for their choice

Thanks for the reply.  There isn't a radio button for user input, unfortunately.  See the screenshot, below.  I can certain create a table to pull this info in, but I'd rather just have a text input for now.  I'm not sure why I don't see these options and my permissions are wide open.  Thanks again for the reply!

Thx for the screen shot,  That is actually a Multi-select field type, not Multiple choice.  I don't see an option to change that field type. 

One option is to make a field field of type Formula text. 

Make the formula be 

ToText([my multi-select field])

Then change THAT field type back to text.  But then you will need to look at field usage for your multi select field and replace it's usage everywhere with the new field, then once it's all working, delete the old field.