you need explain this so we can understand...have you received your 48months extension..and when traveling you need to call and talk to a tier2 officer and get a stamp in your passport before going alot of options..

the you submit online or mail it

When traveling, you will need to show the expired green card and the original receipt notice that comes in the mail. Same with employment

if you know what’s good for you I suggest you don’t travel

I have traveled outside the US 3 times since my conditional Green Card expired. I just presented the expired card along with the extension letter from USCIS. No issues from any agent, no secondary inspection. I didn't switch jobs after it expired but I did reach out to HR letting them know that it was expired and provided them with a copy of the extension letter.

@J N how long take you to receive the letter frome USCIS. after you sent you application I-751

You will need your expired GREEN CARD and extension letter. You should have no problem at all traveling or working . As for your work if your green card is valid even for a day, your employer should not ask for extension letter and should not re-verify your status once your green card expired. However, if it is expired then you should provide both, green card and extension letter. Do not listen to anyone who says do not travel. Even if you were to go for a secondary inspection, Green card holders are generally not denied entry to the United States!! Have a safe travel

@mohammed m about a week