Most likely you will not know what the password is, so here are two methods:
Method 1: Change registry at Regedit.exe
HKLM\Software\Trendmicro\PC-Cillinntcorp\CurrentVersion\Misc.\Allow Uninstall
Change from 0 to 1
* If you are not being allowed to change the registry due to self protection do method 2
Method 2: Go to folder:
C:\Program files\Trend Micro\"Office Scan Client"\OFCSCAN.ini
a. Open the file OFCSCAN.ini with notepad
b. Search (press Ctrl+F) for "Uninstall_Pwd" or "UninstallPwd" (depends on your version)
c. Change password to:
!CRYPT!523D617DF57CBF0E9ACD37611537EBB612F9B6F1C471EB529B89772E71AD9D2431BC212ACF23B7767831E317364
d. Save file and close file and folder
e. The new password for the uninstall will be "test"