Delete or Change Room Assignment for Repeating Event

On an ongoing event for 16 May 2019 with an expiration date of 1/16/ 2020, I am unable to change the RS Room assignment to Cultural Hall. Things I have tried: Delete the "all following events" event beginning on 4/18/2019 after attempting to delete "all following events" beginning with 5/16/2019 event. Neither or those attempts worked. Attempted to change the expiration date to the 5/16/2019 date and save for "only this event" and for "all following events" . At one time, when I deleted the RS Room, and added the Cultural Hall, it seemed to save, did not display RS Room on the screen. I attempted to add the event that will be using the RS Room on to 5/16/2019 date, and received the blocked message. Never had this problem before. I appreciate your help! Judy Winn

Is the Cultural Hall available for all of those dates? Even if there is no event, there might be a restriction that conflicts with one of those dates. You'll need to check the building calendar.

Thank you for your prompt response. I have been doing this since 2011 and have never had this problem.
I have taken the RS Room and the Cultural Hall off of the event.
Display of the Event from display only is: Rooms: Serving Area, Kitchen
RS Room is still marked if event is edited.
Still Blocking when I attempt to add RS Room to the new event.
I Deleted Serving Area, Kitchen and deleted the event. Displayed the event for May and
it was gone! YAY! Displayed the same event for June, still there! YAY!
Went back to May and the event is still there, just as when I started. UGH!
I tried deleting the event, the entire series, and got the message that the request has failed and to contact Tech Support.