Being fired from a company, collecting a pension now, want to re-apply to work part time

Terry do you know if a company fires an employee, but after awhile theystart collecting their pension, like some at age 55, can they lose the pension IF they get re-hired? This happened to me…before I was fired the company I was with got rid of the pension plan and just kept 401k for employees. So a few years later, I’d like to apply to get rehired- but at a different facility and department, to work part time. The company is short handed and I have time in my schedule to handle this. 2 former coworkers of mine are now managers. One is a Senior manager, they have both given me positive responses and encouraged me to re apply. But if this were to happen would I have to give up my monthly pension? Or would this company not know? They have a separate retirement services vendor/company handle the current remaining pensions. I certainly would not want it taken away. Sorry this is probably a really out of the ordinary type of question.