Reinstall packages from another source/Vendor without broking dependencies

There is various situations leading to the wish to reinstall packages from another source/Vendor without broking dependencies.
It is not so easy when continuity of services is an important need.
To avoid difficulties, try to make it with iterative manner, "package set" by "package set".

This is the steps which can be followed for each iteration:
- define with the greatest precision the packages which must be updated (this post can help for this),
- define the dependencies which might be broken while removing regarded packages (this post can help for this),
- ensure there is another source for each package which must be reinstalled, for instance with yum:
yum search packageName1 ... packageNameN
- with great caution, remove the packages regardless to dependencies:
rpm -e packageName1 ... packageNameN --nodeps
- finally, install the new version from wanted source, for instance with yum:
yum --disablerepo=unwantedSource install packageName1 ... packageNameN
- ensure there is no problem, particularly about dependencies:
package-cleanup --problems

As final check, restart the services which may have been affected to ensure there is no warning/error.