I want to change a particular rows\'s cell value, I have the row Id. and I have tried using the following. But it doesnt work.
$(\"#my-jqgrid-table\").jqGrid
Here is the correct way according to the documentation :-
$("#my-jqgrid-table").jqGrid("setCell", rowid, "Currency", "New value");
Check that all variables are correct as what you did seems correct. loadOnce has no impact, you must have a mistake elsewhere.