Convert a Field from Edit (Read) to Read Only

Hi, 
So Using the CB auto Action, would it be possible to convert a Read (editable on the front end) to "Read ONLY"   after a specific condition has been met?
For example, a certain "Field A" can be edited as often as the front-end user wants to, but as soon as a specific condition has been met it changes to READ ONLY and cannot be edited from the front end.

Thanks
 

There is no per-user read only state for fields. To have fields only editable under certain conditions I recommend using CB Conditional for that. This can hide the field when editing it is no longer permitted.