You can use a spell-like ability as if it were a higher spell-level equivalent than it actually is.
Prerequisite: Spell-like ability at caster level 6th or higher.
Benefit: Choose one of your spell-like abilities (subject to the restrictions below) to use at a heightened level up to three times per day (or the ability’s normal use limit, whichever is less). The spell-level equivalent of the heightened spell-like ability is two higher than its normal level (to a maximum of 9th level), with all effects dependent on spell level (including saving throw DCs) calculated at the higher level.
The spell-like ability you wish to heighten can be chosen only from those abilities that duplicate a spell of a level less than or equal to ½ your caster level (round down), minus 2. For a summary, see the following table.
| Spell Level | Caster Level to Heighten |
|---|---|
| 0 | 4th |
| 1st | 6th |
| 2nd | 8th |
| 3rd | 10th |
| 4th | 12th |
| 5th | 14th |
| 6th | 16th |
| 7th | 18th |
| 8th | 20th |
| 9th | — |
Special: This feat can be taken multiple times. Each time, you apply it to a different one of your spell-like abilities.
Source: Complete Arcane, page 80.