You'd have to run the dockutil command in a loop to for all user's home folders to remove Yammer from each person's dock, or use the --allhomes option. This will only remove Yammer from all docks, not replace it with the new path. If you wanted to replace it with the new path you might need to loop another dockutil command after installation to add Yammer back like so:

# You'd do this for each user.
dockutil --add /Users/USERNAME/Applications/Yammer.app

I could go into more detail but you might be able to write the script with what I've provided.

@sidharth.bhalla On second thought, I figure I'd help more. Here you go.

#!/bin/bash

# https://www.jamf.com/jamf-nation/discussions/31175/remove-question-mark-from-dock 

userList=$(find /Users -type d -maxdepth 1 -mindepth 1 | grep -v Shared)

killall 'Yammer'

for userHome in $userList; do
    if [[ -e "$userHome/Applications/Yammer.app" ]]; then
        echo "Yammer.app found in $userHome/Applications; deleting."
        /bin/rm -Rf "$userHome/Applications/Yammer.app"
    else
        echo "No Yammer.app installed in $userHome; skipping."
    fi
    dockutil --remove 'Yammer' --no-restart "$userHome" 2> /dev/null 
done

killall Dock

exit 0