Messages in TBD status in RWB IE message monitoring

Hi

I have messages in TBD status in RWB message monoitoring and log version of messages displayed in SXMB_MONI.

I understand that restarting XI_AF_MESSAGING from NWA will flush out the queue , However would like to understand

1. Once flushed out,  will the message be out into next level of processing or will it be in cancelled .

2. Is there any alternative apart from restarting the services. The issue mainly occured due to some slowness in PI and I would want these messages to be cancelled and should not be transferred to the receiver application .

Your advise is much  appreciated

Thanks

Anusha