You can merge two lead, account, or contact records. (so only these records can be merged)
- Select a record. Then, press the Ctrl key while you select the second record.
- In the Records group, click Merge.
- In the Merge Records dialog box, select which record to make the new master record.
- Select the fields from each record that you want to include in the master record. Fields that are shaded will overwrite the corresponding unshaded field during the merge operation.
- When you are ready to merge the two records, click OK.
- When you receive the message The selected records are merged and the subordinate record is deactivated, click OK.
- In merge operation the master record will inherit all child record’s of subordinate records. So the winning record will contain all the child records. The subordinate record will be deactivated with no associated records.
if you select one record in the Grid, the Merge Button will be enabled and once you will click it, the 1st record will be populated where as the 2nd one will be blank. see the below image
if you select one record in the Grid, the Merge Button will be enabled and once you will click it, the 1st and 2nd both records will be populated. see the below image
Also there is an option to directly choose the values from two records. If for a field there is value present in both the records then master records value will get selected here. For this user need to select the option shown in the below image.