You can't delete an attached receiver. You need to create a new receiver to be able to delete the current one. Depends on your journal and receiver definitions, but it could be as simple as
Then DLTRCV if you have the receiver name handy, or WRKJRNA, go to the receiver directory, and delete it from there.
If you no longer need the journaling at all, delete the *JRN first, then it will let you delete the *JRNRCV.
Another way to go is to setup a threshold size, and allow the journal to manage the receivers by itself. CRTJRNRCV manually with a THRESHOLD(<size in KB>). Then specify that name on CHGJRN, and take a look at the MSGQ(), MNGRCV(), and maybe DLTRCV() keywords. At the very least, even with MNGRCV(*USER), you'll get a message in the MSGQ() when the THRESHOLD() size is reached.
I found out that if I install the license program for 5761SS1 option 42 HA Journal Performamace. Then I can delete the receiver by using the command DLTJRNRCV OPTION (*IGNINQMSG). WHen I did that it deleted the receiver that was taking up 14% of the disk and created an new receiver.
Ah - that's another scenario. When you delete and you get an (I C) message, it's confirming you really want to delete it even though you haven't saved it since it was detached. If you have saved it at least once since it was detached, you don't get that message.