Edit Repeat Series Bug

I'm using Zoho Crm for my cleaning business. We have several hundred clients.
We are using the "events" as "cleanings." So, if we clean mrs. smith's house every
monday, we make a repeat event (cleaning) for her every monday. If we clean mrs
jones every other tuesday, we make an event (cleaning) for mrs. jones for every other
tuesday. We make this a repeat event for as long as far in the future as the system allows.

Here's where problem initiates:

Mrs. Smith calls and says, "can we begin changing our cleanings to every tuesday starting on December 1st."
Remember, it's only September, and we still have to keep all the cleanings on every monday for her up
through December 1st. So, we go into events on for mrs smith on December 1st, and click on Edit Repeat Series,
and make sure the date is on December 1st, and make sure we change the "check mark" from monday to tuesday.

Here's Problem with Crm:

ALL OF THE Monday cleanings in September, October, and November now are deleted because we edited the entire repeat series- EVEN though we went to the December 1st event, we wanted to ONLY edit the series from that point forward.

MY HOPE:

Is there an easy way we can complete the edit without losing the events in September, October, and November cleanings. Please help, thanks.