Hi karthik,
As usual, I seem to be lost again trying to understand what you are trying to do.
With a <space> between the first word of the above command and the <equals-sign>, command runs a utility named JobId with one or more arguments (depending on the output from the two awk commands in your script) where the first argument's first character is the <equals-sign>. The echo command after that line will print an empty line unless JobId had been assigned a value somewhere else.

Furthermore, JOB_ID and JobId are not even close to being the same thing AND with no CODE tags I have no idea what value you are saying the output of that awk command was. And, since you haven't shown us any sample file named Response.xml we have no way of recreating the input you are feeding into that script to try it out ourselves.

The echo of an unquoted variable expansion is only going to produce a single <newline> character at the end of the single line of output it produces; so you can't possibly want tr to change that <newline> character into a <comma>? And, you're invoking sed two more times to enclose your results in <single-quote>s, but you don't show any <single-quote>s in the expected output you say you want to store into the shell variable NEW_VAR. So, again, I'm very confused about how this code might be expected to produce the output you want.

Unless you want to run a loop processing the individual job IDs produce by the first awk script above, why not just have it print the results you want in the format in which you want them to be printed instead of producing output you don't want following by invoking four more utilities to reformat the output?

Making the wild assumption that the awk script you showed us produced two output lines with each containing a single Job ID and that you want to set NEW_VAR to a string containing just those two Job IDs separated by a <comma>, we should be able to produce aMUCH more efficient single awk command to produce the output you want to store into the variable NEW_VAR. But, of course, with no sample input to work with, I can't determine whether the script above that calls awk twice is expecting to find two Job IDs on a single line input file or is expecting to find one Job ID on each of two input lines. Therefore, I can't suggest an awk command that might work for you. Either way there is no need for two awk commands, two sed command, atr command, and two command substitutions.