In general:
* strict Version/Release Control,
* source/binary code repository and
* of course CCB with agreed & signed off by Business approval rules
should help.

BTW. What do you mean by Post/Pre implementation CRs?

I'm an ITIL Expert certified professional. At my work I simply help people. Over last years I observed that despite of amazing computer power growth, end user services are still not as good as they should be. I found that IT universities teach more about hardware and software than about people behav...

I do confirm - IT depends. Mainly on how much time you can allocate to make some progress on Problem Tickets because every investigation needs time. It also depends on nature of your tickets, whether you can seek for workarounds or to formulate definite solutions as change requests: * workarounds so...

The best option is to involve users who requested the Change. They can perform User Acceptance Tests and give positive feedback after deployment (both on TEST and PROD environments). Nevertheless in bigger organizations: - Requestor might be different to person who formulated detailed User Requireme...

"RACI model / authority matrix is often used to map roles & responsibilities to processes and activities"

Read more on:
itsmacademy.com/files/ITSM%20Academy_Role%20with%20ITIL_Webinar.pdf

If it would be a part of a bigger service -> component
If this will be the dedicated service with its own SLA/OLA -> just use service

I worked for a moment in such setup (3 timezones: EU, US, Asia) in critical system with high volume of tickets. Here are some challenges we experienced: - if you pass the ticket to another timezone it won't necessarily speed-up the ticket resolution in case clarifications from end-user are needed (o...

Few out of my mind: - re-prioritization (justification if this is really critical incident from End User or Business perspective) - prioritization (if you have limited resources and many critical incidents at once) - fixing it (search Knowledge Mgmnt DB effectively and discover workarounds or soluti...

In my opinion you cannot avoid such situations, because the help desk is for users and shouldn't be protected from them (unless you close the door:) Think about implementation of following things: 1. Make registration of the ticket extremely easy for Users: - nice email address plus stickers with th...