Air carrier Ground Employee reported software issues while attempting to correct a code error. Ultimately; the error was corrected and flight was closed out.

Narrative

An hour prior I was notified that we had a dry ice shipment going on Flight XX by our operations agent. As it was my first time working a mainline flight with a NOTOC; I asked another crew chief; Person A about how to complete the process; and what I would need to make sure the flight went out on time. I loaded the 22 lbs shipment of dry ice; and handed the NOTOC form to the pilot to sign; and informed him of the weight and contents of the package; and gave the required paperwork to the pilots at 15 and 10 minutes to departure respectively. I closed out the flight; and was informed 30 minutes later that the aircraft was still waiting on the taxiway after we had safely pushed out the flight from Gate XX. Once I was told this by our operations agent; I contacted load planning and asked them to reopen the flight to correct my mistake. I tried to correct it using the scanner; and when I did; the code that I had corrected repopulated; and wouldn't let me remove it. I called in Person B; who quickly told me to call Person C for assistance. I called and he was unable to assist in getting the line deleted. I was then advised by Person A to call flight operations; and after I was on the phone with them; I was able to close out the flight; but not before the aircraft had to return to the gate. I realized the event occurred when I was informed by the operations agent; Person D; that the aircraft was still waiting on the taxiway. The event occurred due to a lack of consistently handling dangerous goods. Our station only has one mainline flight on my shift per day; and I'm not always assigned to it. I've only been actively working as a crew chief for 8 months; and I made an error; even with assistance; but it's not something our station has to handle often. My first course of action was to look for help from those who had more experience in the position than I had in this position. I reached out to Person A; Person B; Person E; and Person C. I tried to correct it on the scanner; and when that didn't work; I tried to correct it. It was finally resolved when I reached out to flight operations and they removed the discrepancy. Suggestions: For one; I would suggest more exposure and training in dealing with dangerous goods. I would also suggest an IT related fix; because this is a prevalent issue. When weight is removed from a mainline flight; sometimes it will repopulate; and won't allow a proper close out until you contact flight operations.