Help with merging two sets of data

Hi,
I am hoping someone can explain a simple way of achieving what I need.

I have two large Bill of material spread sheets, one contains new data, one contains old data.
I need to merge the two without losing any information.

The original spread sheets had different column headings and I have incorporated both sets of headings onto my new spread sheet.
I have copied both sets of data onto the one spread sheet and to make things simpler for me, I have changed the font colour on both the old and the new.
So I now have multiple lines of red font data and multiple lines of green font data, I have then sorted these by part number A-Z, and here is where I need help.
On multiple lines, I have blank cells which I need to copy one line up, but only if the part numbers match.
If I just drag them to copy them, I will be doing this into the New Year, as there are around 3000 lines of data.

I know some basic formulas, but not to the standard I need.
Your assistance will be gratefully received.
Many thanks

Hello Ginge1966, welcome to the forum.

Looking at your example, and reading what you want, can you describe exactly what you mean by "one line up"? There are examples in your sample where you have a cell that is blank for red but populated for green, as well as populated for red but blank for green. What would you like in each instance?

Also, would you combine the data first as you did above?

Is this exactly how your data is presented? That is, is all you are missing within the merged spreadsheet is the level # from column B within every odd numbered row?

I think I understand what you are trying to do...I'm just trying to figure out if the example you provided is a good example of how your data is currently setup; because if it is, you could simply pull the column B data down one row and have it all match...but I'm thinking that your data is probably more disorganized than in your example?

Could you post a sample of the source data, maybe separated out by sheet (before you merge them)?