How to Update and parameterize POST parameters where the post content type=text

We have to run a script where we have to change the value for one of the field name on webpage, as a part of POST parameters section we are only having a single line e.g.
{"type":"EXP","name":"ValueName02","description":"DescName01","exportPassword":"Test@12340","criteria":{"version":1,"page":1,"resultsPerPage":1000}
(which was recorded during the recording of user path)

In the above line is there any way(s) so that we can update the value of only field at each iteration so that can make a unique request with each iteration.

Thanks in Advance.