Replace a value of Nth field of nth row

Using Awk, how can I achieve the following?

I have set of record numbers, for which, I have to replace the nth field with some values, say spaces.

Eg:
Set of Records : 4,9,10,55,89,etc
I have to change the 8th field of all the above set of records to spaces (10 spaces).
Its a delimited file.

Thanks in advance.

Show us some sample input; show us the desired output for those inputs?

How are the record (line) numbers supposed to be given to awk ? (Are they in a shell variable, a file, hardcoded into one of the awk script's BEGIN clauses???)

What is(are) the field delimiter(s) in your input file(s)?