There are a number of components which, for various reasons, have one or more pins missing from the normal sequence. Because Easy-PC requires sequential pin numbering in symbols, creating these does, at first sight, seem to be impossible. That is not so, as the necessary adjustments can be made at component level.
To keep this a simple as possible, when creating the symbol, as many pins as possible should have their correct numbers for the component. To illustrate this, consider a reed relay in a 16-pin DIL package, but with only the end 8 pins present. These will be numbered 1, 2, 7, 8, 9, 10, 15 and 16. The symbol can be created with pins 1, 2, 7 and 8 in the correct position, with the remaining numbers, 3, 4, 5 and 6 used for the higher numbered pins. You may find it easier to create the symbol with the most convenient pin numbering, then use the renumber pins function to reassign them once the symbol is otherwise mechanically correct.
When the component is being created, from V17, select the 'Pin Assignments' tab to display the table (the default view for earlier versions). Use the 'Assign pins 1:1' function to assign the pins, then double click in each on the incorrect boxes in the 'Component Pin Name/Number' column and overtype with the correct number. Note that when the editing is finished, you must click on a different cell to close the final edit. As you do this, you will see that the numbering displayed in the preview image is updated to match, so at the completion of this process, the footprint should be correctly displayed.
Now you can save the finished component to a library and use as normal.