From a Home screen, tap Contacts (located at the bottom).
If unavailable, navigate: Apps > Contacts.
From the Contacts tab, tap the appropriate contact.
Tap Edit contact (located at the top).
Enter/edit any of following information then tap Save (located in the lower right):
To change the account type, tap the Dropdown menu located at the top then tap the desired account (e.g., SIM, Google, etc.).
Available options may vary.
To add a pause (a 2-second delay between numbers) or wait, tap then tap P or W as appropriate.