If I understand you correctly, you want only a 1D array with all data appended linearly.
How are you building your array? If you use the build array node, righ-click on it and select "concatenate inputs" (of course you need to start with a 1D array in this case.)
If you want to convert your array after the fact, use "reshape array" and make a 1D array with length set to the product of the dimensions of the 2D array (depending on your arrangement, you might need to transpose the 2D array first).
There are many other possible scenarios. If you want more detailed help, attach a reduced version of your code.