Hw do I change username in RTC and mapping.csv so user does not lose project work?

In our system, we keep our users in the mapping.csv file then import the user into RTC using the standard process.

My question is that occasionally, we get users who either get married, divorce or for some other reason have a change to their LDAP username credentials.

Example: Mary Smith has been in the RTC system for sometime, I had already imported her into RTC using the Manage Users - Import Users routine.  She has been working on a number of projects which she is a member of.  She logs into RTC using her LDAP credentials

User ID: msmith 

Password: ********

In the existing mapping.csv file I have her entry listed as msmith,JazzUsers.

I as an Administrator of the RTC application get a notice in my email, that Mary Smith is now Mary Jones, and the security team has changed her LDAP User ID from msmith to mjones. 

How do I go about getting her to be able to log into RTC using her new User ID?

I can imagine that I can change her entry in the mapping.csv file to mjones,JazzUsers

How do I go about getting her into or changing her credentials to login into RTC, so that she doesn't lose the connection she had with the projects or work she has done in the projects she is currently a memebr of? 

NOTE: Her email address within the Company system wil also have changed from msmith@company.com to mjones@company.com.