There are a number of D&D 4e character creation options that allow players to substitute one ability score in place of another under certain conditions. Here are some examples:
Auspicious Birth or Born Under A Bad Sign backgrounds
Benefit: You substitute your highest ability score for Constitution to determine your initial hit points.
... or ...
Melee Training feat
Benefit: Choose an ability other than Strength. When you make a melee basic attack using a weapon with which you have proficiency, you can use the chosen ability instead of Strength for the attack roll. In addition, you can use half of that ability’s modifier, instead of your Strength modifier, for the damage roll.
What options are there for 4e characters to substitute one ability score for another?