I am using a sumif function and would like the criteria to point to the cell
where the text characters are instead of typing them as I have do it for 50
names and 12 months. I also want to use a wildcard*. I thought of taking out
the "" and have used = signs which are not accepted and typed in the cell
reference but it does not work.

Sheet 1 has names in Column B and Values associated with the names in Column
H.

In sheet 2 I setup the sumif calculation in B2.
=SUMIF(Sheet1!$B$2:$B$281,"*Wendy*",Sheet1!$H$2:$H $281). I want to be able
to replace Wendy with a cell reference of *a2*

Sheet 2 Example
A B C
1 Name Jan Feb etc
2 Wendy (FORMULA)
3 John

Thanks in advance.