Hello @suman_kumar_dey,
I guess that “yum” requested “php71u-xml” and CentOS repository provided “php56u-xml”.
Similarly, “yum” requested “php56u-common” and CentOS repository provided “php-common-5.3.3”.
Have you installed the “php71u-xml” package with the repository option?
For example, “--enablerepo=ius-archive”.
If you have installed “php71u-*” and “php56u-*” packages with the repository option, you should use same the option for re-installation.
Regards