Add data to row that already contains data

I want to enter data for the same product but it needs to be done on different days, with two different entry forms, so the row will already contain data points and I will have to pick the row and add more data in the following cells of the same row (not a new one)

example:
on day 1 I enter: on day 2 I add on to the same row

Day Product Weekday processing date amount operator


Is there any way that vb can find the row with the product I need and then just add data into the same row with a second entry form?