I recently read an online inquiry by a Red Notice subject who had been advised that her Red Notice was "in the process of being removed" by the prosecuting attorney. The subject wondered how long the removal would take.
Every INTERPOL member country has its own National Central Bureau (NCB), which acts as a liaison with INTERPOL itself. Red Notices are issued at the request of the member countries, and the information contained in the Red Notice, as well as the information contained in the files kept by INTERPOL, actually belongs to the member country that supplies that information to INTERPOL. That ownership was discussed in more detail here (back when INTERPOL had only 188 member countries.)
The requesting member country may decide to publicize the Red Notice or not, and also may decide to withdraw the information at any point. For example, if a Red Notice is no longer needed because a person has been acquitted or an underlying charging document has been found to be invalid, the member country has the capability of instructing its NCB to arrange the removal of its information from INTERPOL's files.
Once such a decision has been made, the removal can and should be almost immediate. If the member country is efficient, the subject should not need an attorney to facilitate that process.
As always, thoughts and comments are welcomed.