I've run into this in the past and am running into again now. In the past the issue seemed to work itself out w/o me really knowing what I did.

I have a Futaba R203GF receiver that is paired to another controller (I think its a Futaba 2PV or 2PL ..not sure the exact name). It hasn't been used in that car for a long time as I sold the car. I would like to use this receiver with my Futaba 4PX (in another car). Problem is I can not get it to bind w/ my 4PX, however when I turn on my 2PL it is bound. ...how do I unbind from one controller and re-bind w/ another?

When I turn on the receiver and try to connect to my 4PX (I am getting a blinking green light on the receiver then it turns off). I've tried toggling the receiver type via the controller as well as holding the "bind" button down on the receiver ...nothing. It's like the ID is locked into the receiver and won't allow me to bind w/ any other controller.

help!

I've had problems binding Futaba receivers such that I had to almost touch the antennas of both transmitter and receiver together to get it to work. 6-12" inches apart wasn't good enough.

There is no unbind option, the binding will overwrite the info. Did you set the transmitter to S-FHSS mode?

thanks, ...i'll try moving them closer next time I try to re-bind a receiver ..although they were about 12" apart ..but perhaps touching would be better.
I actually found a solution, it doesn't solve the issue, but it is a solution.

I have the same type of receiver in another car, I tried and successfully was able to bind another receiver that was previously being used. AND I took the problem receiver and re-bound it w/ no issue to a different controller. The receiver I was having trouble linking to my 4PX and couldn't bind was easily able to bind w/ a cheaper Futaba controller w/ no issue. Odd ...but after playing some musical chairs w/ my receivers they are all bound.

darn about not having an "unbind option" ...yes I did set the transmitter to S-FHSS mode (and all the other modes and back again as I wasn't having luck w/ S-FHSS initially).
I just can't get this one receiver to bind w/ my 4PX, -yet it did bind w/ another less expensive lower model Futaba controller w/ no issue. (so like in my previous post, I just had to do some swapping of receivers between vehicles until I found one that would re-bind to my 4PX).

..the funny thing is my expensive 4PX has had this issue on more than 1 occasion (where it has trouble binding to a receiver), however I have yet to experience this w/ my cheaper 2PL or 3PV controllers. In fact the same receiver will bind just fine w/ my 2PL and 3PV but not the 4PX (which was a higher end controller). (note, this is even after toggling between the various s-fhss, t-fhss, etc protocols).

Maybe the answer is in here:
Futaba 4px link with S-FHSS problem

Having used (and still using) compatible receivers, some only like HRS, PPM modes.