How To: Convert a grid from one datum/projection method to another

Problem/Symptom:
Can Oasis montaj or Target convert a grid from one datum to another?

Can I convert from one projection method to another in the same (or different datum)?

Can I convert a grid from geographic to projected XY (or vice-versa)?

Environment:
Oasis montaj, Target, any version (this solution is specific to 7.0 with regards to menus and menu items; the actual process is the same in any previous version).

Resolution:
Here are the steps to convert a grid from one datum to another (we will use NAD27 to WGS84 as an example):

1. Go to Grid and Image | Utilities | Reproject Grid File(s);
2. Browse to the original grid that you wish to reproject and click [Next];
3. The Coordinate System dialog appears - this dialog will show the datum of the original grid file (NAD27) that you chose in step 2: do not modify the datum at this point;
   Click [OK];
4. The New Re-Projected dialog opens; here you will enter in a name for your newly created grid file. Click [Next] once you have done this;
5. Another Coordinate System dialog will open which also contains the datum information of the original grid. Here you will modify the datum such that it reflects the new datum (WGS84); once you have chosen the new datum click [OK];
6. Click [Finish] in the New Projected Grid dialog;
7. You can verify that the datum has been changed by going to Grid and Image | Properties. Alternatively, you can right-click on the newly created grid in the Project Explorer and select Metadata from the context menu. This information will be located in the Coordinate System area of the metadata tool.

Please note that the same steps above apply to re-projecting a grid's projection method using the same or different datums, and also applies to converting geographic to projected XY (or vice-versa).