Windows Remote Assistance has been a built in feature since XP.
For security reasons the account you access in Remote Assistance is the account requesting help, and UAC prompts on the remote machine (anything on the "secure desktop") are not remoted, and have to be agreed to by the person you are assisting. However, if you have setup an Admin account on that machine, you can still use any RunAs tools of your choice/familiarity (runas.exe, Shift Right Click Run as User, PowerShell Start-Process -Credential) to escalate to your Admin account (so long as they don't need you to input your password on the "secure desktop").
For security reasons the account you access in Remote Assistance is the account requesting help, and UAC prompts on the remote machine (anything on the "secure desktop") are not remoted, and have to be agreed to by the person you are assisting. However, if you have setup an Admin account on that machine, you can still use any RunAs tools of your choice/familiarity (runas.exe, Shift Right Click Run as User, PowerShell Start-Process -Credential) to escalate to your Admin account (so long as they don't need you to input your password on the "secure desktop").