Talk to your boss - ask them what your role is with the new Admin. If you're the one they are supposed to report to and/or get their training from, tell your boss that there must be some mis-communication going on with you and the person who was promoted; because they are the ones giving the new Admin instructions. Tell your boss you don't want to confuse the Admin, or train them improperly, and make them wondering who's giving them the correct instructions/who they should be listening to. Basically you're narc-ing, the professional way. Without blaming, point fingers, accusing, and being a tattle tale. It's a must. You need to resolve the conflict.. so you definitely have to say something. If you go to your boss, it'll be resolved quickly and without question.

I've gone to my boss before in the way you suggested, and she agrees 100%. But she isn't the aggressive type; she won't follow through with this employee. And things might improve for awhile. But every now and then, when both me and my boss are gone, "Zelda," this co-worker will tell me, "Oh, I let Jenny leave a little early on Friday." My response? "Jenny already worked that out with me, as her supervisor." Things like that. Or Zelda will try to give Jenny "instructions" on a task that I've already gone over with her. Or Zelda will try to do something "Jenny" should do, probably because it was her "old job" before, and I won't let her do it. That's gotten better, though but the problem is that I don't supervise Zelda, and she doesn't take me seriously because she is jealous of me. She point-blank told me that today. She admitted that she is very jealous of all the praise Jenny and I get for various reasons, and that everyone in the office excludes her and says things that hurt her feelings. Now what do I say to that? She's just plain irritating. So every now and then, she starts "trouble." She'll just cross those boundaries, and when I explain that she can't do "Jenny's" job anymore or that we have to follow XYZ procedure, she gets her feelings hurt because you have to use a firm tone with her to get her to understand, and she takes it as "unkind." Things have gotten better, but every now and then, she'll just do something like try to tell Jenny what she should be doing.....it's irritating.

I've gone to my boss before in the way you suggested, and she agrees 100%. But she isn't the aggressive type; she won't follow through with this employee. And things might improve for awhile. But every now and then, when both me and my boss are gone, "Zelda," this co-worker will tell me, "Oh, I let Jenny leave a little early on Friday." My response? "Jenny already worked that out with me, as her supervisor." Things like that. Or Zelda will try to give Jenny "instructions" on a task that I've already gone over with her. Or Zelda will try to do something "Jenny" should do, probably because it was her "old job" before, and I won't let her do it. That's gotten better, though but the problem is that I don't supervise Zelda, and she doesn't take me seriously because she is jealous of me. She point-blank told me that today. She admitted that she is very jealous of all the praise Jenny and I get for various reasons, and that everyone in the office excludes her and says things that hurt her feelings. Now what do I say to that? She's just plain irritating. So every now and then, she starts "trouble." She'll just cross those boundaries, and when I explain that she can't do "Jenny's" job anymore or that we have to follow XYZ procedure, she gets her feelings hurt because you have to use a firm tone with her to get her to understand, and she takes it as "unkind." Things have gotten better, but every now and then, she'll just do something like try to tell Jenny what she should be doing.....it's irritating.